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The American sitcom The Big Bang Theory, created and executive produced by Chuck Lorre and Bill Prady, premiered on CBS on September 24, 2007. The series initially centers on five characters: roommates Sheldon Cooper and Leonard Hofstadter, two Caltech physicists; Penny, a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon's friends and co-workers aerospace engineer Howard Wolowitz, and astrophysicist Rajesh Koothrappali. Over time, several supporting characters have been promoted to starring roles: In season 3, microbiologist Bernadette Rostenkowski, and neuroscientist Amy Farrah Fowler are introduced, and later become Howard's wife and Sheldon's girlfriend, respectively. Both were promoted to main cast in season 4. Stuart Bloom, a comic book store-owner who has been a recurring character since season 2, became a main character in seasons 6 and 8. Leslie Winkle, a promiscuous physicist who had an affair with Howard and Leonard on separate occasions, briefly became one of the main cast in season 2 before disappearing from the series.
The series also features numerous supporting characters, each of whom plays a prominent role in a small group of episodes. Included among them are parents of the main characters, their dates and their coworkers.
|Leonard Hofstadter||Johnny Galecki||Main|
|Sheldon Cooper||Jim Parsons||Main|
|Howard Wolowitz||Simon Helberg||Main|
|Raj Koothrappali||Kunal Nayyar||Main|
|Leslie Winkle||Sara Gilbert||Recurring||Main||Guest|
|Bernadette Rostenkowski-Wolowitz||Melissa Rauch||Recurring||Main|
|Amy Farrah Fowler||Mayim Bialik||Guest||Main|
|Stuart Bloom||Kevin Sussman||Recurring||Main||Recurring||Main|
|Alex Jensen||Margo Harshman||Recurring|
|Barry Kripke||John Ross Bowie||Recurring|
|Beverly Hofstadter||Christine Baranski||Recurring||Recurring||Recurring|
|Dr. Eric Gablehauser||Mark Harelik||Recurring|
|Dr. and Mrs. Koothrappali||Brian George and Alice Amter||Recurring|
|Mary Cooper||Laurie Metcalf||Recurring||Recurring||Recurring|
|Priya Koothrappali||Aarti Mann||Recurring|
|Stephanie Barnett||Sara Rue||Recurring|
|Wil Wheaton||Wil Wheaton||Recurring|
|Mrs. Wolowitz||Carol Ann Susi||Recurring (Voice only)|
|Zack Johnson||Brian Thomas Smith||Recurring||Recurring|
Main characters are divided into two groups, original main characters and those who have been promoted to main character status since season two.
With the exception of injury to the actors, these characters have appeared in all episodes.
Dr. Leonard Leakey Hofstadter (Johnny Galecki) is an experimental physicist with an IQ of 173 who is originally from New Jersey and received his PhD at age 24, spending at least some of his time at Princeton University. He shares an apartment in Pasadena with colleague and friend Dr. Sheldon Cooper. Unlike his equally geeky friends, Leonard is interested and quite adept in building interpersonal and social relationships with others. Compared to his friends he is relatively successful with women. The writers have toyed with a romance between him and next-door neighbor Penny since the pilot, with their unresolved sexual tension being a major force for drama. Leonard dated Penny for most of Season 3, although they had dated briefly at the end of Season 1. Aside from Penny, Leonard has had romantic relationships with coworker Leslie Winkle, physician Stephanie Barnett, an unnamed French literature PhD, and North Korean spy Joyce Kim. Following his breakup with Penny, Leonard began a relationship with Raj's sister Priya in Season 4, and it is implied they had a brief sexual encounter before the start of the series on an occasion when Priya visited Raj. The two attempted a long-distance relationship after Priya moved back to India, but Leonard eventually broke up with her in Season 5 after she admitted to cheating on him with her former boyfriend. In Season 5's "The Beta Test Initiation", Leonard and Penny start dating anew though their relationship is rocky. Over the next two years they talk of marriage and each have unsuccessful proposals until the end of season seven when they become engaged. Leonard's family includes other accomplished scientists: his mother, Dr. Beverly Hofstadter, is a world-renowned psychiatrist, his sister is a biologist and his father an anthropologist. Also, his brother Michael is a Harvard law professor. It is mentioned in the season 2 episode "The Maternal Capacitance" that Leonard is the least successful member of his family. He is also known to be lactose intolerant and cannot process corn, as Sheldon states in "Pilot". Leonard also plays the cello. The cause of the elevator not working is also due in part to Leonard (and Sheldon) as the experimental rocket fuel he was developing was improperly mixed within their apartment and Sheldon threw the canister into the elevator shaft right before the explosion.
Dr. Sheldon Lee Cooper (Jim Parsons) is a theoretical physicist, possessing a Bachelor of Science, Master of Science, PhD, an ScD, and an IQ of 187. Originally from East Texas, he was a child prodigy, starting college at the age of 11, and receiving his PhD at age 16. He is cold and calculating, and refrains from any form of physical contact if possible. Sheldon exhibits a strict adherence to routine to the point of exhibiting obsessive–compulsive personality disorder, performing specific activities on specific days and specific times, such as doing the laundry on Saturday night at 8:15. Any disruption to this routine distresses him enormously. A running gag has him always knocking on doors or other surfaces in a pattern of three knocks and one call repeated three times, which he has to complete no matter what. He has forced Leonard into signing an absurdly exhaustive "Roommate Agreement", and later enters a similar "Relationship Agreement" with Amy Farrah Fowler. Sheldon has great difficulty identifying sarcasm and irony and responding in kind, and a recurring topic is his efforts to acquire these skills. He has also enormous difficulties lying or even keeping a secret, giving himself away with wild facial tics and implausible statements. He is however fond of occasionally playing a prank, which he typically punctuates with his trademark exclamation "Bazinga!". Sheldon has a superiority complex and makes no effort to hide his contempt for other people's intellects, often making highly inappropriate comments. A common joke is his inability to drive, although he did receive a learner's permit. Sheldon loves comic books and science fiction like his friends, but to the point of being obsessed about them, and is a fan of Spock, a fictional character of the Star Trek franchise. Unlike Leonard and Raj who come from intellectual families, Sheldon stands out from his own relatives. His father, George, whose death pre-dates the series, was described as a stereotypical Texan who liked football, skeet shooting, and heavy drinking, his mother, Mary, is a devout Evangelical Christian, who does not possess anything near Sheldon's intellect (though she displays a great deal of common sense); his twin sister, Missy, and as-yet unseen brother, George Jr., were both described by Mary as being "dumb as soup". His fraternal twin sister who later has a baby boy makes Sheldon an uncle. He meets Amy Farrah Fowler in the Season 3 finale and starts a highly unusual and very slowly evolving relationship with her and by season 7 they having started kissing each other. Previous to this, he has also exhibited some affinities with Leonard's equally unemotional mother.
Penny (surname has not yet been revealed) (Kaley Cuoco), is Leonard and Sheldon's neighbor across the hallway. Originally from a small town outside Omaha, Nebraska, she was a waitress and occasional bartender at the local Cheesecake Factory until season 7 and is an aspiring actress. Her educational qualifications (she had dropped out of community college) are a constant source of disparaging comments from Sheldon. She has dated several men during the course of the series, including Kurt, Stuart, and Zack, but her recurring romantic interest is Leonard. Leonard pursued Penny during season 1; they dated briefly at the start of season 2 which led to some awkwardness; they began dating again and were a couple for most of season 3, but she broke up with him after he told Penny he loved her and she was not ready to reciprocate. Penny and Leonard begin to date again "slowly" during the fifth season, though he does upset her by impulsively asking her to marry him during intercourse at the end of season five. After several unsuccessful proposals from both sides, Penny realizes that her happiness is derived from her relationship with Leonard and they become engaged. She has a tense relationship with Sheldon, whose nerdy and obstinate personality often exasperates her, but they are ultimately good friends, helping each other out in various situations. By season four, Penny also begins to socialize more with Bernadette and Amy, who frequently hang out in Penny's apartment, go out together and comfort each other. Bernadette and Amy are both shown to be simultaneously envious of and threatened by Penny's more outgoing personality. Not much is known about Penny's family, but it is mentioned in the series that her father, Wyatt (portrayed by Keith Carradine), raised her like a boy, her mother smoked marijuana while she was pregnant with her, her sister shot her husband while they were intoxicated and her brother is a meth dealer. Cuoco began being credited as Kaley Cuoco-Sweeting, starting with the season seven episode, "The Convention Conundrum".
Howard Joel Wolowitz (Simon Helberg) is an aerospace engineer at Caltech's Department of Applied Physics with a Masters in Engineering who often hangs out at Leonard and Sheldon's apartment. Unlike Sheldon, Leonard, and Raj, Howard has no doctorate, and often gets disparaged as a result, especially by Sheldon. He defends this by pointing out that he has a master's degree in Engineering from MIT and that the equipment he designs is launched into space, unlike the theoretical work of his friends. In the season 5 finale, Howard goes to the International Space Station on Expedition 31. Howard lives in Altadena with his domineering, belittling and unseen mother who treats him like a child. While he sometimes expresses irritation at this treatment, for the most part he appears to prefer it.[episode needed] Howard dotes on his mother and participates in many of her daily routines. A recurring gimmick in the series is Howard and his mother communicating with each other from different rooms by yelling, a habit which Bernadette also adopts in later episodes. His father left them when he was eleven, and Howard gets visibly distressed when the subject comes up. Howard fancies himself a ladies' man and attempts pick-up lines whenever a woman is present, which often come off as inappropriate and disgusting, although he has dropped this habit since he started going out with Bernadette.[episode needed] He is Jewish, but he is not very serious about his faith, and does not keep kosher. For example, when the group's favorite Chinese restaurant raised the price of pork, Howard remarked, "It's getting tougher and tougher to be a bad Jew." However, he does observe Sabbath and the Jewish holidays. In the pilot episode, it is shown that he is a polyglot and can speak English, French, Mandarin, Russian, Arabic, and Farsi, along with fictional languages like Klingon and Sindarin. He is asthmatic, allergic to peanuts, almonds, and walnuts, prone to canker sores and pink eye, succumbs to seasickness, has an incredibly high genetic risk of heart illness, and has transient idiopathic arrhythmia. In Season 5 episode 4, it is shown that he knows American Sign Language. Howard dated Bernadette briefly in season 3. After some difficulties, they resumed their relationship in season 4, which culminated in their engagement. In the season 5 finale, Howard and Bernadette are married on the roof of the apartment building shortly before he has to leave for Kazakhstan where he is to be sent to the International Space Station. In season 6, he finally leaves his mother's house and moves into Bernadette apartment.
Dr. Rajesh Ramayan "Raj" Koothrappali (Kunal Nayyar) is Howard Wolowitz's best friend, and yet another genius of the group; his name is usually shortened to "Raj". He is originally from New Delhi, India, and he works in the Physics department at Caltech, where his area of expertise is particle astrophysics. He lives in an apartment in Pasadena. As with his friends, he is mutually involved with and obsessed with science fiction and comic books in general, and is usually the one to propose various real-life questions derived from such works, such as the functions of the tails of the Na'vi in the film Avatar. He is also a fan of Harry Potter. Raj dislikes India, Indian food, and Indian music, he also appreciates the Indian lullabies his mother sang to him and the catchiness of Hindi phrases. Raj is a Hindu and believes in karma (reincarnation), but eats beef. Raj is very shy around women, and finds himself unable to speak to or while in the presence of them unless he drinks alcoholic beverages, or he believes he has done so. When Penny, Amy and Bernadette are around, Raj usually whispers what he wants to say to Howard or Leonard, who then repeats or responds to what Raj says out loud, although at times Howard will embarrass him by saying something completely different and inappropriate. Despite this, Raj has sometimes ended up in bed with women, leaving the other guys perplexed. Unlike his friends however, Raj has many quite feminine interests such as reading Archie Comics and Twilight and watching chick flicks such as Bridget Jones's Diary. A recurring joke in the series has people, including his parents and Leonard's mother, speculating that Raj might be gay due to his feminine interests and his close friendship with Howard, with whom he has arguments similar to those of a married couple. However, Raj has always stated that he is straight, but metrosexual. He has had an infatuation with Penny, and secretly wrote love poems about Bernadette. Raj comes from a very wealthy family in India, and often communicates with his parents, Dr. and Mrs. Koothrappali, via webcam. He has a younger sister, Priya, who is mentioned to have dated Leonard briefly before the series timeline began and dates him again in Season 4, breaking up with him in Season 5. After making a brave speech about not being embarrassed to be single, Raj started seeing a shy and sweet woman named Lucy. Lucy has many things in common with Raj including her fear of being in large crowds. In the season 6 finale, Raj finds he can now talk to women without alcohol, however he never stops talking. In season 7, Raj begins to interact with women ending the season with a red-headed girlfriend named Emily.
The following characters have been promoted to main character status since season 2. Leslie Winkle and Stuart Bloom are only credited in episodes in which they appear. Bernadette and Amy Farrah Fowler were promoted to main character status in season 4, and their images were included in the main title sequence from the first episode of season 6.
Dr. Leslie Winkle (Sara Gilbert) (appeared in eight episodes total, four credited as main cast) is an experimental physicist who works in the same lab as Leonard. Her first appearance was in the third episode of season one. In appearance, she is essentially Leonard's female counterpart, equipped with the black framed glasses and sweat jackets. She also happens to have a lazy eye. She is one of Sheldon's arch-enemies, due to their conflicting scientific theories and Sheldon's strong misogyny. Though they both consider each other to be intellectually inferior, Leslie is much wittier than Sheldon, regularly calling him "dumbass" and besting him in their exchanges. Leslie has had casual relationships with Leonard and later Howard, considering it a completely physical reaction to her body's cycles – her voice remains emotionless even during moments of extreme physical intimacy. Leslie's final appearance was in the season 3 finale, as the writers said they did not know how to work in the character full-time. After Penny broke up with Leonard, she got intoxicated, had intercourse with him, then pushed him away. Distraught, Leonard asked for intercourse with Leslie. Leslie responded, "Let me think about it," before slamming the door on him.
Dr.[a] Bernadette Maryann Rostenkowski-Wolowitz (Melissa Rauch): (has appeared in 101 episodes total, 96 credited as main cast) is originally a waitress and coworker of Penny's at the Cheesecake Factory, which pays the way for her graduate studies in microbiology per "The Creepy Candy Coating Corollary". A recurring joke in the series is in reference to Bernadette and her lab team handling dangerous or infectious specimens, leading to accidental by-products or exposure to diseases, in some cases resulting in Bernadette ending up in quarantine. Instances include her trying to remember whether she washed her hands while she worked with penicillin-resistant gonorrhea or creating a cold medicine that may cause acidic tears. She is of Polish origin and Catholic upbringing, and is frequently seen wearing a cross necklace. She is generally a friendly and good-natured individual, quickly making friends with Penny and Amy, as well as the rest of the gang, but occasionally shows signs of mania, e.g. when she got into a fight with Amy over a parking space Sheldon and Howard were fighting over, and when she explains her interest in microbiology as being because she feels like a God to the bacteria she is studying. She has complete influence over both her father and her husband as she freely overrules her father without being contested and directly supervises Howard's expenditure by giving him allowance money. On one occasion, she was also able to control Sheldon, putting it down to knowing how to deal with stubborn children.
Penny first introduced Bernadette to Howard on Leonard's half-willing request. During the first date, Bernadette and Howard do not find any common field of interest until they find out that they both have domineering mothers. After three dates, Bernadette blindsides Howard by declaring that three dates is the threshold for deciding whether they want a long term relationship. She is not impressed by Howard's failure to reply readily and is even more repulsed by Howard's subsequent impulsive proposes to her. However, when Howard sings a heartfelt song for her at the Cheesecake Factory, she declares that it is the most romantic thing anyone has ever done for her. A lengthy offscreen breakup occurs when she catches Howard engage in cybersex. After a brief apology from Howard, she consents to restarting (as opposed to resuming) their relationship. In the season 4 finale, she obtains her doctorate and is subsequently hired by a pharmaceutical company with a high salary. While preparing for their wedding, Bernadette is shocked and repulsed when stories of secret sexual escapades from his past are released, although once again, the apology and reconciliation occurs quickly in the same episode. They get married the day before he leaves for his upcoming mission at Houston. During season 6 and 7, the newlyweds battle issues involving Howard's difficulty in readjusting to being back on Earth, the struggle to keep a healthy relationship with Howard's mother, and arguments over expenditure. Despite numerous problems and squabbles, Howard and Bernadette exhibit the only steady relationships on the series.
Dr. Amy Farrah Fowler (Mayim Bialik) (has appeared in 95 episodes total, 89 credited as main cast) is a neuroscientist (which corresponds to Bialik's real-life Ph.D.), and Sheldon's love interest in the series. She has a Ph.D. in neurobiology, with a research focus on addiction in primates and invertebrates, occasionally mentioning such experiments as getting a capuchin monkey addicted to cigarettes or starfish addicted to cocaine. Raj and Howard found Amy through an online dating site after secretly setting up an account using Sheldon's name and information. The site matches her to Sheldon, and the two share many similar traits. Once she and Sheldon meet, she becomes, as Sheldon puts it, a girl who is his friend, but not his "girlfriend." They briefly ended their friendship when they got into an argument over whose field of study was superior. The two initially communicate via computer, but at the encouragement of the group, she starts hanging out with the gang in person. Early on, Amy is, essentially, a female counterpart to Sheldon. During this time, she is almost coldly rational while displaying little emotion, is awkward in social situations ranging from endearing to embarrassing, is sometimes condescending towards those of lesser scientific knowledge and has little or no desire for physical intimacy. In Season Five, after Amy went out on a date with comic book store owner Stuart, Sheldon decided to solidify their relationship as boyfriend/girlfriend with a 31-page "Relationship Agreement". Amy began a campaign in "The Launch Acceleration" to increase Sheldon's feelings for her by becoming more involved in his interests like video games and Star Trek, and treating him as his mother had. During Howard and Bernadette's wedding ceremony, Amy is disappointed when Sheldon says that he hopes that the two of them are as happy together as he is alone. Later as Howard is launched into space, Amy is surprised when Sheldon spontaneously takes her hand for comfort. Despite her best efforts, however, he repeatedly resists all of her attempts at persuading him to engage in physical intimacy though they are regularly holding hands at Amy's insistence at the beginning of season 6. By mid-season when Sheldon was caring for her when she had the flu, Sheldon has some intimate views of Amy pushing him further toward a normal relationship with her. She has also provided Sheldon with consoling hugs and was slapped on the rear by an intoxicated Sheldon, telling everyone that she is a great gal. Amy tried to move into his apartment when Leonard temporarily vacated it. After being prodded by Barry Kripke about his girlfriend, he lied that they were having sex, though he admitted to Penny that it might really happen between him and Amy and later admitted it to Amy while also engaging in Dungeons and Dragons' intercourse game play. Nevertheless, her frustration is frequently played for laughs from that point onward. In the Season 7 episode "The Locomotive Manipulation", Sheldon sarcastically says he will give Amy the romance she wants, then he passionately kisses Amy on the lips for the first time and enjoys it.
While early on Amy was ambivalent and often condescending towards Penny and Bernadette, she later spends more time with them even at the expense of her time with Sheldon. As her appearances have progressed, she has shed her strident, aloof personality for a stereotypically feminine and social one, although she retains some social awkwardness. Her feelings for Sheldon have also grown considerably over time and considers him to be ideal in almost every way, though she sometimes becomes as annoyed and frustrated by Sheldon's quirks as his other friends do. Amy also intensely wants her relationship with Sheldon to progress to include sexual intimacy, a drastic departure from her early days as a member of her circle of friends. She has come to consider Penny a very close friend, sometimes referring to her as her "bestie," and, on another occasion, admitting her entire social life revolves around her. Penny herself is fond of Amy, on one occasion making an effort to salvage their friendship after she accidentally hurt her feelings. To her dismay, however, Amy often fails to grasp the concept of "girl talk," by talking about feminine hygiene and anatomy when in her presence and at times being brutally honest. Also, Amy often demonstrates an infatuation towards her, and occasionally Bernadette, to whom she is still rather condescending though still considers a close friend. These including making inappropriate comments about Penny's body and Bernadette's personality. After attending a science convention with Bernadette in "The Hofstadter Insufficiency", Bernadette and Amy found common interests and became better friends. When she feels that Leonard is interested in her, she admits to Penny that she has a better shot getting her into bed than Leonard. In episode 8 of the fifth season, she suggests that Bernadette's bridal shower should consist of naked bridesmaids washing each other, and she proposes that the bachelorette party consist of a Native American sweat lodge and women dancing around painting fertility symbols on the bride's naked body. Her more arrogant side is shown in "The Pulled Groin Extrapolation", where she is convinced that Leonard has fallen for her after he accompanies her to a friend's wedding and gives her a chaste kiss on the cheek, even though he has no such feelings. In "The Benefactor Factor", it is revealed that she is technically engaged to Saudi Arabian Prince Faisal who resides in Riyadh, who is the source of much of her lab's funding. Amy can also play the harp. In "The Scavenger Vortex," it is suggested that she attended Harvard University.
Stuart Bloom (Kevin Sussman) (appeared in 33 episodes total, seven credited as main cast) Stuart runs The Comic Center of Pasadena, the comic book store that the guys patronize. Stuart is characterized by his low self-esteem and loneliness, which result in pathetic attempts to engage with women and win favor with the main cast. This is despite owning his own (albeit troubled) business, and being a talented portraiture artist who attended the Rhode Island School of Design.
During Stuart's first appearance, the guys brought Penny to the store and he managed to ask her on a date. The date went fine until Stuart was dragged into discussing comic books by Sheldon, leaving Penny bored. On a second date with Penny, Stuart asked for Leonard's advice, but feeling threatened, Leonard ultimately gave him bad advice. The date went fine, but when Penny was getting romantic with Stuart she mistakenly called him "Leonard", leaving him devastated. He also briefly went on a date with Amy in season 5; although Sheldon interrupted the date to solidify his relationship with Amy. Stuart was the partner of Wil Wheaton in a trading card game tournament in which they defeated the team of Raj and Sheldon. As Stuart runs a comic book store, he has an almost encyclopedic knowledge of comic books and superheroes. In the Season 4 episode "The Toast Derivation", he mentions that he is in financial trouble and that the comic book store is now also his home. In "The Justice League Recombination", he states that he works 70 hours and clears an average of $1.65 per hour after expenses, so his income per week would be $115.50. At Howard's bachelor party during the "The Stag Convergence" episode, Stuart uses his toasting turn to tell Howard how lucky he is by contrast to Stuart's own existence. In the Season 6 episode "The Bakersfield Expedition," Penny asks Stuart for advice about comics, and he sullenly answers, "Don't own a store that sells them." During "The Decoupling Fluctuation", Stuart becomes close friends with Raj and starts hanging out with the gang as a replacement for Howard while Howard is in space. Before accepting this, Sheldon quizzed Stuart as to where he went to school (Stuart has an art degree). Sheldon concedes to allow Stuart to be in the group, calling him "fake-Wolowitz" and equating his past career choice in art to Howard's as an aerospace engineer as "equally ridiculous". When Howard returns from space Sheldon wants to dismiss Stuart from the group but Raj objects. Leonard tie-breaks on the basis that they are receiving a 20% discount in Stuart's store. Sheldon relents after Stuart offers to go as high as 30%. Initially, Sheldon had stipulated that Stuart must act like Howard while in the gang's presence.
These characters appear in several episodes. The list is sorted by alphabetic order using first names.
Alex Jensen (Margo Harshman): An attractive Caltech graduate student who appears in season six. She is hired by Sheldon to review his kindergarten and elementary school notebooks for any possible Nobel Prize winning research and attend to the tasks that Sheldon perceives a waste of his own valuable time. Amy is at first jealous until she sees Alex instead flirting with an unresponsive Leonard. After repeated flirts by Alex, Leonard finally realizes that Alex is making advances toward him. While proclaiming his loyalty to Penny, Leonard is flattered. Sheldon interferes (with the perceived intention of mitigating a situation that needed none) by lecturing Alex, but only succeeds in insulting her. After Alex files a sexual harassment complaint, Sheldon is forced to apologize and is ordered take a university-mandated online sexual harassment course. Because Sheldon considers his own time is too valuable to waste on it, Sheldon asks Alex to take the course instead.
Alex scores some points with Sheldon after he sends her out to buy Amy a Valentine's Day gift, and Sheldon likes it so much that he keeps it for himself.
Barry Kripke, Ph.D. (John Ross Bowie): A coworker of Leonard and Sheldon's who frequently clashes with them. He works in plasma physics. Kripke has a case of rhotacism in which he pronounces the letters "R" and "L" as "W" in much the same way as Elmer Fudd from Looney Tunes and Gilda Radner in her "Baba Wawa" sketches. Until Season 7, it was never clarified he was aware of his impediment, however in "The Discovery Dissipation", when Sheldon mocks his impediment, Barry appears visibly hurt and tells Sheldon he has no control over it. In his first appearance, he pits his robot, the Kripke Krippler, against the men's robot, M.O.N.T.E., in an unofficial robot fight. On another episode, Sheldon attempts to befriend Kripke in order to gain access to an open science grid computer to carry out research, but it turns out to be futile, as Kripke has no control over the computer's usage time. Kripke continues his antagonism towards Sheldon, when he pulls a prank on Sheldon when the latter is a guest on NPR's Science Friday. Sheldon tries to befriend Kripke another time when he is feeling excluded by his friends, but Barry connects more with the others in Sheldon's new proposed group. Kripke purchases an iPhone with voice recognition technology, but due to his rhotacism, the device is incapable of understanding his verbal "wequests", prompting him to deride it as ineffective. In Season 5's "The Rothman Disintegration", Kripke and Sheldon battle over a retired professor's office. At Howard's bachelor party during the "The Stag Convergence" episode, Kripke uses his turn toasting to complain that there are no strippers at the party. In the Season 6 episode "The Cooper/Kripke Inversion", Kripke and Sheldon are forced to work together on a proposal involving fusion reactors, which involves an exchange of work. Sheldon is shocked to discover that Kripke's work is more advanced than his own, and he tearfully admits as much to Amy. Kripke assumes that Sheldon is in a sexual relationship with Amy, and that has led to his work quality declining, and Sheldon does not deny it (although this appears to be just a convenient excuse since his work is inferior to Kripke's). Kripke likely holds a doctorate, as he is seen applying for tenure at the university in "The Tenure Turbulence."
Dr. Beverly Hofstadter (Christine Baranski): Leonard's overly analytical mother, Beverly is a neuroscientist as well as a psychiatrist. She is Sheldon's female equivalent regarding neurotically strict speech patterns, lack of social conventions, and attention to detail. The two of them share an odd non-romantic attraction to each other, which culminates in her kissing him after becoming intoxicated. She reveals in one episode that she and Leonard's father "are getting a divorce". She had frequently implied that the two have not had "coitus" since Leonard was conceived. One of her famous books is "Needy Baby, Greedy Baby," in which she describes an infant's (aka Leonard's)unrealistic nurturing expectations. Sheldon often refers to the book when frustrated with Leonard's attempt to obtain some of his personal needs in their relationship. In one episode she also relates to Leonard that his vague memory of living with an ape and learning sign language was part of an experiment she conducted during Leonard's early years. Beverly reunites Leonard with his long-lost ape friend after Leonard's insistence that she do so. Leonard sees his mother as cold and un-nurturing, even telling the group that one time he made a hugging machine just to get hugs. The lack of Beverly's maternal feelings and actions toward Leonard have led to his being determined "King of the Foreplay" because of his obsessive need to please.
Beverly diagnosed Raj with selective mutism and considers Raj and Howard's relationship to be an "ersatz homosexual marriage". Beverly mentions that Leonard's brother and sister are more successful in their respective fields than he is. Ironically, as displayed in "The Maternal Congruence" episode, Sheldon is closer to Beverly than her own son is. In both 2009 and 2010, Baranski was nominated for an Emmy Award for Outstanding Guest Actress in a Comedy Series for this role. She returns via Skype for the season 5 premiere, and in the season 7 episodes "The Raiders Minimization" and "The Status Quo Combustion".
Dr. Eric Gablehauser (Mark Harelik): The head of the Physics Department, Dr. Gablehauser is the group's boss at the university. In his first appearance, he fired Sheldon after Sheldon insulted his intelligence. Eventually, Sheldon was rehired because Gablehauser became romantically interested in Mary Cooper, Sheldon's mother. Dr. Gablehauser was also responsible for introducing child genius Dennis Kim to the university and for hosting the Physics Bowl.
Dr. V. M. Koothrappali (Brian George) and Mrs. Koothrappali (Alice Amter): Raj's parents in India, they communicate with their son via video chat and constantly try to arrange dates for him. They want their son to marry a woman of Indian descent, and give them grandchildren. Mrs. Koothrappali is especially worried that, despite Raj being old enough to marry, the closest they have to a daughter-in-law is "that little Jewish boy Howard". Although in many episodes Raj mentions that he grew up in poverty, his friends remind him of the contrary by pointing out that Dr. Koothrappali is a gynaecologist, drives a Bentley and employs servants, for which Raj replies that the Bentley is leased and that some of the servants are children. The Koothrappalis enjoy Doogie Howser reruns, which are apparently new to India. Other than Raj, they also maintain contact with Priya Koothrappali via video chat whenever she is out of India. They also had some anger towards Leonard when it became apparent that he was dating Priya without their knowledge. According to Sheldon, they are Richie Rich rich.
Emily Sweeney (Laura Spencer): A dermatologist who initially contacts Raj through an online dating site. The reluctant Raj has Amy contact her as his wingman instead. Amy and Emily exchange emails and find they have a lot in common. They both went to Harvard, are doctors, and like crocheting and Chaucer. Emily doesn't like Raj's inability to correspond with her directly, and when Amy and Emily meet to have coffee, Raj barges in to show that he is not a passive guy. Emily calls him a weird guy with no boundaries and leaves. She also ditches Amy for their next get together. In "The Indecision Amalgamation", Raj meets Emily again and apologizes. She gives him another chance and agrees to go out to dinner with him. Later on, Raj finds out that his ex-girlfriend Lucy wants to see him again and he finds himself dating two women, although this does not bother Emily. In "The Relationship Diremption", Raj and Emily have dinner with Howard and Bernadette. Howard figures they should do it quickly because Raj is bound to mess up his relationship very quickly. Upon meeting Emily, Howard recognizes her because he had a blind date with Emily sometime near 2009 before he met Bernadette. He had a sick stomach, had to use the bathroom and clogged the toilet. Since he was too embarrassed to tell her, he escaped through the bathroom window. Emily reveals that she and her friends refer to Howard as "Clogzilla". In "The Anything Can Happen Recurrence", Raj and Howard watch the gore-fest "House of 1000 Corpses" because Emily wants to watch it with Raj. They are both turned off and wonder about someone who likes this type of movie. On their date, Raj tells Emily how he feels about it and she also wonders about someone who likes this film. She also admits that it turns her on, so Raj immediately starts it so they can watch it. In "The Gorilla Dissolution", Raj and Sheldon find Emily at the movies with another guy. Later she visits him to talk and reveals that the guy was her tattoo artist who had been asking her out for weeks and she did so just to end the obligation. She mentions a tattoo on her shoulder, one that is not on her shoulder and one that is REALLY not on her shoulder. Emily then then spends the night and in the next episode, Raj reveals that he and Emily are now exclusive. Raj and Emily are still dating in season 8, and she is introduced to Leonard and Penny, the latter to which she is initially cold to. Emily later reveals that she is uncomfortable with the fact that Raj and Penny hooked up in "The Roommate Transmogrification". Emily and Penny later sit down to settle their differences; however after the meeting both women state that they hate one another.
Lucy (Kate Micucci): A woman who shows up at the party at the comic book store on Valentine's Day for people who had no dates. She and Raj hook up and subsequently start dating. She has social anxiety issues, which allows her and Raj to connect. On their date, she text messages with Raj and, at the end, she offers to kiss him, but chickens out at the last second. Raj and Lucy make up at the end of the episode and continue to date. In the sixth season finale, Raj and Lucy start to get closer and Raj tries to introduce her to his friends. Lucy feels too pressured and breaks up with Raj in a text message at the end of the episode. She returns in the season 7 episode "The Itchy Brain Simulation" to apologize to Raj for breaking up with him via email. This leads Raj to believe the two of them will get back together, but Lucy tells him she is with someone else.
Mary Cooper (Laurie Metcalf): A devout fundamentalist Christian from Texas, Mary is Sheldon's mother. She has two other children besides Sheldon; Sheldon's twin sister, Missy and his brother George, who is shown via a family tree in "The Cruciferous Vegetable Amplification" to be three years older than Sheldon and Missy. To Mary's relief, her other children do not share Sheldon's hyper-intelligence, once commenting to Leonard "I thank the good Lord my other kids are as dumb as soup". She appeared in the fourth episode of the first season, the season three premiere, the third episode of season four, the sixth episode of season five and the eighteenth episode of season seven. Mary herself is not intellectual but is quite wise, though she is prone to making insensitive comments such calling Japanese "kung fu letters" at sushi restaurant, or calling Native Americans "our Indians". Despite her extreme religious views, she is tolerant of other faiths, as evidenced by her serving Raj a dish of chicken after making sure it was not something Indians considered "magical". She also struggles to follow her beliefs sometimes, shown through her affair with another churchgoer in "The Mommy Observation". She is a loving mother and the only one who has ever been able to control Sheldon, with Leonard describing her as Sheldon's "Kryptonite" to Penny. When Penny and Sheldon engaged in a fierce dispute, Penny called for Mary's help, who subsequently called and scolded Sheldon about his actions. Leonard wishes his mother was as loving as Sheldon's mother, although Sheldon himself appears at best ambivalent about her parenting. It is once mentioned by Sheldon that Mary once hit him with a Bible because he refused to eat his Brussels sprouts. She apparently thought something was wrong with her son while he was growing up, as Sheldon will often remark after someone calls him crazy, "I'm not crazy; my mother had me tested!" Though Mary Cooper confirms this, she wishes that she had taken him to Houston for further testing.
Mike Rostenkowski (Casey Sander), first introduced in season 5, is the father of Bernadette. Mr. Rostenkowski is a hardened police officer, who has a rough and rude personality, and often bullies others. He admitted to Howard that he does not like him, but is impressed with him being an astronaut. He appears to have a soft spot for Bernadette, calling her his "little girl." Before he was first seen, Bernadette warned Howard not to mention Jimmy Carter, gardeners, foreigners, homosexuals, Sean Penn, Vatican II, organic food, gun control, recycling, or Howard's Jewish heritage, indicating that he is far-right-wing. Whilst initially cold to Howard, his respect for Howard grew, however, when he learned Howard had been selected to become an astronaut. When Howard told him of his terror of going to space, Mr. Rostenkowski said "It's gonna be okay, son. A pretty girl like Bernadette... She'll find a new guy." In "The Fish Guts Displacement", Howard and Mike get pushed into a fishing weekend by their spouses and it turns out neither of them want to go. Mike suggests that they go to a casino to shoot craps. They bond somewhat and he tells Howard to call him Mike and no longer "Sir". In "The Thanksgiving Decoupling," his wife is out of town and Bernadette gets him to come to Howard's mother's house for Thanksgiving dinner though he would rather watch football at home. Since Sheldon knew football thanks to his father, Mike and Sheldon bond and get drunk together. Mike later tells Howard that he isn't "all that bad", however he retorts that he is drunk. In "The Table Polarization," he, Bernadette, Raj and Mike Massimino (via web chat) perform an intervention on Howard's decision to go back to space (he had to be prodded by Bernadette to agree about loving him). He mentioned that Howard asked him to shoot him in the foot, at which Howard insisted was a joke.
Priya Koothrappali (Aarti Mann): Raj's younger sister, introduced in the fourth season. Having graduated at the top of her class at Cambridge, she is one of the lead attorneys at India's biggest car company. It is disclosed upon her first appearance in "The Irish Pub Formulation" episode that she and Leonard had a relationship five years earlier (without her parents' or Raj's knowledge) when she was in town, and that Leonard had been much more invested in the relationship than she. Leonard even offered to relocate to Delhi to be with her. He tries to keep their relationship a secret from the guys, but Sheldon discovers Priya in their apartment. Leonard eventually reveals to the rest of the guys that he has spent the night with Priya, as he is unable to bear the burden of keeping the secret. Priya returns to Los Angeles for business in "The Cohabitation Formulation" and she and Leonard decide to try and have a real relationship, over the protests of Raj. It upsets Raj to know that his sister is having sex with one of his best friends (sometimes in Raj's bed). Priya soon becomes jealous of Penny and asks Leonard to stop spending time with her, but Leonard is unable to do so. Priya contests Sheldon's roommate agreement with Leonard, employing her legal background to deny Sheldon power over Leonard, but Sheldon drafts a new agreement. Sheldon then blackmails Leonard into signing it by threatening to tell Priya's parents she is dating Leonard, which she cannot bear because they want her to date an Indian (although her father would accept her dating Howard due to his belief that Jews are financially savvy and do not drink much). In the fourth season finale, it is revealed she is moving back to India and has not told Leonard, which Leonard interprets as the end of their relationship, leading him to expose their secret relationship to her parents. During Season 5, although they are separated, with Priya moving back a month earlier than expected, they nonetheless remain in-touch via webcam, having a cyber-dinner date/breakfast date. At Howard's suggestion, Leonard and Priya also attempt to simulate intercourse via webcam, but when it comes time for her to remove her clothing, Leonard's screen freezes up because of exceeding the bandwidth. Leonard later manages to get cue cards to help himself with a seduction speech to Priya, but while delivering it to her, he inadvertently reveals to her parents that they are cyber-dating (they were in the same room as she when he called), with them acidly asking for him to continue with the speech. After Leonard tells Priya about his attraction to a comic book enthusiast named Alice, Priya admits to cheating on him with her former boyfriend, which visibly upsets Leonard. She claims that it is not a competition, to which he replies that it is and that she won. Then he switches off his laptop. In the next episode, Leonard refers to himself as single, indicating he and Priya have broken up as a result of their last conversation.
Dr. Stephanie Barnett, MD (Sara Rue): A doctor and highly distinguished surgical resident at Fremont Memorial, Stephanie is picked up in a bar by Howard but when his plan to let her drive the Mars rover fails, she leaves Howard's office with Leonard and the two immediately show an attraction to each other. Sheldon begins meddling in Stephanie and Leonard's new relationship in an effort to strengthen it, since in his eyes, Stephanie is the only "tolerable" mate Leonard has had. After several weeks of dating, Stephanie officially begins living with Leonard in his and Sheldon's apartment. However, after much hesitation, Leonard tells her to move out because he is uncomfortable with the pace of the relationship. They are not seen breaking up on camera. Series co-creator Bill Prady said of the relationship: "Stephanie was a chance for Leonard to learn that just because someone loves you, doesn't mean you'll love them back". Stephanie did her medical internship at Lawrence Memorial in Galveston, Texas, which is where Sheldon was born.
Wil Wheaton (a fictionalized version of the real actor of that name): In the season three episode "The Creepy Candy Coating Corollary", Sheldon enters a trading card game tournament (Mystic Warlords of Ka'a) to confront Wil Wheaton over an incident that occurred in 1995 when Sheldon was devastated because Wheaton (Wesley Crusher in Star Trek: The Next Generation) failed to show up at a fan convention that Sheldon took a 10-hour bus ride to attend (in which he had to "twice violate his personal rule of no relief on a moving vehicle"). In the final match, Sheldon is about to defeat his hated rival, but Wheaton tells Sheldon that the reason he missed the convention was because his grandmother had died. In sympathy, Sheldon deliberately messes up his next move in order to benefit Wheaton. Wheaton reveals that he lied about his grandmother, then wins the game by taking advantage of the opening Sheldon left him. Wil Wheaton makes a second appearance in the episode "The Wheaton Recurrence", where he uses gamesmanship again, breaking up Leonard and Penny's relationship in order to win a bowling competition against the main characters. In "The 21-Second Excitation", Wheaton appears at a screening of Raiders of the Lost Ark and uses his celebrity status to go to the front of a long line. This antagonizes Sheldon, who derides him as the "Jar Jar Binks of the Star Trek universe." Wheaton and his entourage effectively prevent Sheldon and the guys from attending the screening when the last seat in the theater goes to the person directly in front of them in line. Ultimately, Sheldon steals the prints of the film and Wheaton leads a mob of angry Raiders fans after Sheldon. In the season five episode "The Russian Rocket Reaction", Wheaton appears to be genuinely sorry for his past actions and gives Sheldon a signed Wesley Crusher action figure as a way of thanking Sheldon for being a fan. His gesture is met with a renunciation of his "mortal enemy" status, and a hug from Sheldon. With Wheaton, LeVar Burton, Leonard Nimoy, Brent Spiner and George Takei also having appeared on the show, Star Trek is the most represented franchise on the show in terms of guest appearances. At Howard's bachelor party during the "The Stag Convergence" episode, Wil films the toasts and uploads them to the Internet, getting Howard and Raj in trouble with Bernadette and showing that he has not lost all of his "evil" quirks. In the season six episode "The Habitation Configuration", Wheaton appears in a Star Trek-themed episode of Sheldon's webseries Fun with Flags, and insults Sheldon's girlfriend (and the webisode's director), Amy. After he ditches Amy to hang out with Wheaton, Amy gets angry at Sheldon; he later unknowingly becomes inebriated and tries to start a fistfight with Wheaton, demanding an apology.
Mrs. Debbie Wolowitz (voiced by Carol Ann Susi): Howard's controlling, belittling Jewish mother. The character is not shown on-screen with the exception of one episode in season 6 in which her body, but not face is briefly shown and also as a skeleton in season 7. Mrs. Wolowitz's raspy voice is heard usually in scenes at her house, which she shared with Howard until his marriage. She talks to Howard always by yelling at him from another room, which results in awkward conversations with Howard yelling back at her. In an early episode, when the guys hear her yelling in a masculine voice, they ask Howard if that was his father, to which Howard replies "If she grows any more hair on her face, yes".
She is also described as being enormously obese (especially in the arms), and wearing a wig and painted-on eyebrows. Mrs. Wolowitz seems to be oblivious about Howard's work as an engineer and treats him like he is still a child. She frequently refers to Leonard, Sheldon, and Raj as Howard's "little friends" (as in, "I made some cookies and Hawaiian Punch for you and your little friends!") and often refers to Caltech as a "school". Howard often makes references to his mother as being a "crazy old lady", but deep down, he is deeply attached to his mother and quite happy to be treated like a child. However, in one episode, Howard attempts to move out after a fight with his mother, but has serious delusions that she is trying to force him to stay, when in actuality, she is urging him to move out, which leads to him staying. In the penultimate episode of season 4, she wants to "play doctor" with Raj when he asks to sleep over.
When Howard reveals that he has proposed to Bernadette and she has accepted, she collapses, causing Howard to panic (and dislocate his shoulder while trying to barge into the bathroom to help her). The timing leads him to believe that she may not like Bernadette (who is Catholic) and has suffered a heart attack from the shock of the news. In actuality, her fainting was due to food poisoning from the food she ate while meeting Bernadette, and was completely unrelated to Howard's news. She has graciously accepted Bernadette as her future daughter-in-law and loves that she is a doctor. She attended Howard and Bernadette's wedding on Leonard/Sheldon/Penny's apartment building roof and can be seen in the satellite picture of the event. The episode "The Spoiler Alert Segmentation" is a major episode in Mrs. Wolowitz's character as she appears on screen for the first time; first walking across the kitchen through the kitchen doors, and then her hands are seen pulling Raj back into the house. Her face is not seen at all, but her appearances in the kitchen scene make her out to be an extremely obese woman.
Zack Johnson (Brian Thomas Smith): A dim-witted, but friendly beefcake-type whom Penny dates after her second break-up with Leonard. Leonard invites Penny and Zack up to the roof to watch his experiment of bouncing laser beams off the moon; Zack misunderstands what is happening. Later, he and Penny go out on a date, but she is so put off at how stupid he is that she runs back to Leonard to have sex, saying that Leonard has ruined her ability to date stupid men. In a later episode, Zack runs into Penny, Bernadette, and Amy at a restaurant, and Amy becomes physically attracted to him. Unlike Penny's other boyfriends, he considers Leonard, Howard, Sheldon, and Raj (whom he calls "the science guys") to be "cool" and makes a genuine effort to get to know them, considering them to be his friends. After accompanying them on a trip to the comic book store (where he and Raj bond over a mutual fondness for Archie comics), he enters a New Year's Eve costume party with them, portraying Superman in their version of the Justice League. He works as the menu designer for restaurants that are owned by or which have hired his father's company to design their menus. In "The Toast Derivation", Sheldon invites him over for a party, where he bonds with Barry Kripke and Stuart as well. It is revealed in season 7's "The Thanksgiving Decoupling" that he was unknowingly married to Penny for three years, after they got intoxicated and attended a wedding chapel in Las Vegas.
These characters appear in fewer episodes, most in just one. The list is in alphabetic order by first name.
A number of Hollywood celebrities and famous scientists have made appearances as themselves. The list is sorted by alphabetic order by last name.