August 1999 was a month with thirty-one days.
The following events occurred during the month:
| August 14, 1999 (Saturday)|
- Work is completed on the Øresund Bridge, connecting Denmark and Sweden.
| August 17, 1999 (Tuesday)|
- A 7.4-magnitude earthquake strikes Istanbul and northwestern Turkey, killing more than 17,000 and injuring 44,000. This earthquake was the first of a long series of unrelated but frequent earthquakes throughout the world during the years 1999 and 2000. Some connected the earthquake to the fact that the Umbra of the solar eclipse of August 11, was right above Istanbul.
| August 26, 1999 (Thursday)|
- Michael Johnson captures the 400 M. world record.
- The pilot episode of SmackDown! aired