Jack Spencer (1920–1998) was an Australian rugby league footballer who played in the 1940s and 1950s, a state representative prop forward who won two premierships with the Balmain club in Sydney.

Spencer had a long top-grade career playing eleven seasons at the Balmain club between 1942 and 1951.

Spencer was a rugged forward who played in two winning premiership teams in 1946 and 1947.

He was the father of another premiership winning Balmain player, named John Spencer, who played between 1966 and 1975.

[2] Spencer died at Bateau Bay, New South Wales on 10 February 1998 aged 77.