Marc Tanguay is a Canadian politician and a member of the National Assembly of Quebec for the LaFontaine electoral district.
On 26 September 2009, he was elected president of the Quebec Liberal Party. He is a lawyer by profession, and studied political science at Université Laval and law at Université de Montréal.
He was elected in a by-election held on 11 June 2012, which was triggered by the resignation of Tony Tomassi on 3 May 2012. Prior to that, he was an unsuccessful Liberal candidate in the 2007 general election in Chambly electoral district, finishing third.