Duncan McMillan "Mickey" MacKay (May 21, 1894 in Chesley, Ontario – May 21, 1940) was a Canadian professional centre who played for the Chicago Black Hawks, Boston Bruins, and Pittsburgh Pirates in the National Hockey League. He also spent time with the Vancouver Millionaires and Vancouver Maroons of the Pacific Coast Hockey Association. Mickey was an important member of the Millionaires team that reached five Stanley Cup finals and won once in 1915. He also won a second Stanley Cup when he helped the Bruins defeat the New York Rangers in 1929.