The 1975 Mr. Olympia contest was an IFBB professional bodybuilding competition held November 4–11, 1975 in Pretoria, South Africa. It was the 11th Mr. Olympia competition and the feature event of the 1975 IFBB International Congress.

The event was filmed for the 1977 docudrama Pumping Iron which featured the rivalry between competitors Arnold Schwarzenegger and Lou Ferrigno as they trained for the contest. Although not released until two years after the event, the success of the film made Arnold Schwarzenegger an international celebrity, contributed to his success as Hollywood actor, and helped establish bodybuilding as a professional sport.

Results
The total prize money awarded was $2,500.

Over 200lbs
Place Name
1 Austria Arnold Schwarzenegger
2 France Serge Nubret
3 United States Lou Ferrigno

Under 200lbs
Place Name
1 Italy Franco Columbu
2 United States Ed Corney
3 Barbados Albert Beckles
4 United States Frank Zane
5 Italy Giuseppe Deiana

Overall winner
Place Name
1 Austria Arnold Schwarzenegger

Notable events
Arnold Schwarzenegger won his sixth consecutive Mr. Olympia title and announced his retirement from professional bodybuilding, although he would later come out of retirement to compete in the 1980 Mr. Olympia