Donald Ralph "Big Mac" MacSweyn (September 8, 1942 – May 21, 1995) was a Canadian professional ice hockey defenceman.
He played 47 games in the National Hockey League (NHL) with the Philadelphia Flyers from 1968 to 1972 and 147 games in the World Hockey Association (WHA) with the Los Angeles Sharks and Vancouver Blazers from 1972 to 1974.
A native of Laggan, Ontario, MacSweyn played for teams in the NHL, EHL, WHL, AHL, WHA, SHL, NAHL, SLSHL, and the OIHA.
After his retirement, MacSweyn returned to his family farm and also was involved in coaching his daughter's hockey team.
This biographical article relating to a Canadian ice hockey defenceman born in the 1940s is a stub.