John James "Jack" Harris (born October 27, 1948 in St. John's, Newfoundland) is a Canadian politician and lawyer. He is a former leader of the Newfoundland and Labrador New Democratic Party.
Harris first became a member of the Canadian House of Commons after winning a by-election in the electoral district of St. John's East on July 20, 1987. Harris was the second New Democratic Party (NDP) candidate ever elected to the House of Commons in Newfoundland and Labrador.
Harris was elected to the Newfoundland and Labrador House of Assembly in the 1990 provincial election and became leader of the provincial NDP in 1992. He was re-elected to the Legislature in the 1993, 1996, 1999 and 2003 elections.