Donald Ralph "Big Mac" MacSweyn (September 8, 1942 – May 21, 1995) was a Canadian professional ice hockey defenceman who played five seasons in the National Hockey League (NHL) for the Philadelphia Flyers. He also played two seasons in the World Hockey Association (WHA) with the Los Angeles Sharks and Vancouver Blazers. MacSweyn played for the senior Lancaster Dodgers in 1963-64 and then turned pro with the Johnstown Jets in 1964-65. His rights went to the Philadelphia Flyers when they purchased the Quebec Aces.