Swimming at the 2008 Summer Olympics – Men's 50 metre freestyle

The men's 50 metre freestyle event at the 2008 Summer Olympics took place on 14–16 August at the Beijing National Aquatics Center in Beijing, China.

César Cielo made an Olympic milestone to become Brazil's first ever gold medalist in swimming. He rocketed to an unexpected triumph in a new Olympic record of 21.30, then the second-fastest in history, powering past the field by 0.15 of a second, a sizable chunk in Olympic swimming's shortest race. The French tandem of Amaury Leveaux and Alain Bernard took home the silver and bronze with respective times of 21.45 and 21.49.

Australia's Ashley Callus finished fourth in 21.62, while his teammate and world record holder Eamon Sullivan was a fraction behind the leading pack in sixth at 21.65. For the first time in Olympic history, no American swimmer had reached the podium in the event, as the reigning world champion Ben Wildman-Tobriner, swimming on the outside in lane eight, pulled off a fifth-place effort in 21.64. Competing at their third Olympics, South Africa's Roland Mark Schoeman (21.67) and Sweden's Stefan Nystrand (21.72) rounded out the finale in seventh and eighth place, respectively.

Earlier in the prelims, Cielo posted a time of 21.47 to erase Alexander Popov's 1992 Olympic record by 0.44 of a second. One heat later, Leveaux established the same record by winning the twelfth heat in 21.46. The following morning, in the semifinals, Cielo lowered again an Olympic record to 21.34 that had been set by Leveaux in the preliminaries under 0.12 seconds.