Robert Charles Pirie (April 30, 1916 – January 22, 1984) was a Canadian freestyle swimmer who competed internationally in the 1930s.

Pirie was unanimously selected as the Lou Marsh Trophy winner for 1939, recognizing Canada's top athlete.

That year, in Hawaii, he broke the 220-yard world record long held by Johnny Weissmuller and finished third in the U.S. national championships in the 110-yard and 220-yard freestyle races, with Japanese swimmers taking the top two spots in both races.

Earlier, Pirie won silver and bronze in freestyle events at the 1934 British Empire Games.

His sister, Irene Pirie, also won individual silver and bronze freestyle medals at the same games.