John Mahaffy (July 18, 1918 – May 2, 2015) was a Canadian professional ice hockey centre.

He played 37 games in the National Hockey League with the New York Rangers and Montreal Canadiens from 1942 to 1945.

The rest of his career, which lasted from 1935 to 1952, was spent in the minor leagues.

Mahaffy was born in Montreal, Quebec.

This biographical article relating to a Canadian ice hockey centre born in the 1910s is a stub.