Monique Gagnon-Tremblay (born May 26, 1940 in Plessisville, Quebec) is a politician in Quebec, Canada.
She was the MNA for the riding of Saint-François in the Estrie region from 1985 to 2012.
She served as Liberal leader of the Opposition in the National Assembly of Quebec from May 1998 to December 1998 and Deputy Premier in 1994 and from 2003 to 2005.
Gagnon-Tremblay has been the member of the National Assembly for Saint-François since December 1985.