Percy Williams OC (May 19, 1908 - November 29, 1982) was a Canadian athlete, winner of the 100 m. and 200 m. races at the 1928 Summer Olympics.

Born in Vancouver, British Columbia, Williams surprised many - himself the most - when he won the Canadian trials and was sent out to the 1928 Olympics in Amsterdam at age 20. To his surprise, he found out that he could easily advance to the final of the 100 m. event. A good start in the final gave Williams the early advantage to win the race. He repeated his performance in the 200 m. to come home with two gold medals - cheered by thousands of enthusiastic Canadians. He showed that his success was not an accident, winning the 100 yard dash at the British Empire Games and setting a World Record in 1930. South of the border, the Americans were not happy. They didn't like being beaten by an unknown Canadian and they were determined to show it was a fluke. The Americans arranged a series of indoor track meets and invited Williams. If the Americans were surprised in Amsterdam, they must have been dazed when Williams won 19 of 21 races in the series. There was no doubt, Williams was the best sprinter in the world.

A pulled thigh muscle stopped his successes for a while, and he never made a full comeback. At the 1932 Summer Olympics, he was eliminated in the quarter-finals. Subsequently, Williams stopped running and became an insurance agent.

In 1979 he was made an Officer of the Order of Canada.

Williams lived with his mother until she died in 1977. After that, he was all alone and living in constant pain from arthritis. Percy Williams committed suicide in 1982.