Gregory ("Greg") Efthimios Louganis (born January 29, 1960 in El Cajon, California) is an American diver who is best known for winning back-to-back Olympic titles in both the 3m and 10m diving events. He received the James E. Sullivan Award from the Amateur Athletic Union (AAU) in 1984 as the most outstanding amateur athlete in the United States. Louganis is of Samoan/Swedish descent and was raised in California by his adoptive parents, a Greek-American couple.
At age 16, Louganis took part in the 1976 Summer Olympics in Montreal, Canada where he placed second in the tower event, behind Italian Klaus Dibiasi. Two years later, with Dibiasi retired, Louganis went on to win his first world title in the same event.
In 1978, he accepted a diving scholarship to the University of Miami where he studied theater, but in 1981 transferred to the University of California, Irvine, where he graduated with a Bachelor of Arts.
The rise of the Chinese to dominance in the sport is in part attributable to Louganis, as the Chinese coaches filmed and studied his performances assiduously, and built their national approach to diving on the mechanics they were able to discern in his technique, and upon their communications with leading coaches such as Hobie Billingsley.
Louganis was a favorite for two golds in the 1980 Summer Olympics in Moscow, but an American boycott of the games prevented him from participating.
Louganis won two world diving titles in 1982. In the 1984 Summer Olympics, with record scores and leads over his opponents, Louganis won gold medals in both the springboard and tower diving events.
After winning two more world championship titles in 1986, he repeated his 1984 feat in the 1988 Summer Olympics, although not without difficulties: he suffered a concussion after hitting his head on the springboard during the preliminary rounds while performing a reverse 2 1/2 pike. He completed the preliminaries despite his injury, and went on to repeat the dive during the finals, earning the gold medal. His comeback earned him the title of ABC's Wide World of Sports "Athlete of the Year" for 1988.
Post-diving and writing career
Louganis posed nude for Playgirl magazine in 1987.
In 1994, Louganis announced that he is gay; he took part in the 1994 Gay Games as diving announcer, and performed an exhibition of several dives to a standing-room only crowd of nearly 3,000 spectators.
In 1995, Louganis's autobiography co-written with Eric Marcus, entitled Breaking the Surface, was published. Louganis revealed that the man with whom he was living had repeatedly abused and raped him and that Louganis was HIV-positive. The announcement caused some controversy because of the belief, as expressed by then-United States Olympic Committee executive director Harvey Schiller, that he should have disclosed his HIV status during the 1988 Olympic games because his diving board injury resulted in light bleeding. Louganis had agonized over whether to disclose his status but was later advised by AIDS expert Dr. Anthony Fauci that the injury posed no danger of infection to fellow competitors. 
Following the announcement of his HIV status, Louganis was dropped by most of his corporate sponsors, with the exception of the aquatics gear manufacturer Speedo, which continued to sponsor him as of 2007.
In 1999, Louganis's second book, For the Life of Your Dog (co-authored by Betsy Sikora Siino) was published.
Since retiring from competitive diving, Louganis has done some acting, most notably appearing in an off-Broadway production of the Paul Rudnick play Jeffrey. As a hobby, he competes at the top level of dog agility with his Jack Russell Terriers. He amicably ended a romantic relationship with former E! television personality Steve Kmetko in 2006 after a seven-year relationship.
- Mandell, Nina. "Catching up with Greg Louganis", Sports Illustrated, 2008-08-02. Retrieved on 2008-08-08.
- Sandomir, Richard. "Agonizing Over Disclosure of AIDS", New York Times, 1995-02-06. Retrieved on 2007-10-28.
- Louganis, Greg; Eric Marcus (1995). Breaking the Surface. New York: Random House, 7. ISBN 0679437037.
- "On Course With Greg Louganis" (November 2007). Clean Run 13 (11): 16–17. Retrieved on 2008-01-22.