The Honourable Diane Marleau, PC, MP (born June 21 1943 in Kirkland Lake, Ontario) is a Canadian politician. After serving as a regional councillor, she entered federal politics and was first elected to the Canadian House of Commons as the Liberal MP for Sudbury in the 1988 Canadian election and has been re-elected in every subsequent election.

When Jean Chrétien's Liberals were elected to government following the 1993 Canadian election, Marleau joined the Cabinet. She served as minister of health and minister of amateur sport from 1993 to 1996 when she was demoted to the position of minister of public works and minister of supply and services . During her term these positions were amalgamated into the position of minister of public works and government services. In 1997 she was moved to the position of minister for international co-operation and minister responsible for La Francophonie before being dropped from the Cabinet entirely in 1999.

After being sent to the backbench she became critical of Chretien's leadership and vocal in her support for Paul Martin to replace him.

In 2004, after Martin became prime minister, he appointed Marleau Parliamentary Secretary to the President of the Treasury Board and to the Minister responsible for the Canadian Wheat Board.

Marleau's husband, Paul Marleau, is a prominent businessman in Sudbury who ran for mayor of the city in 2003. (See Ontario municipal elections, 2003.)