John Gilbert Layton was a Canadian academic and politician who served as the leader of the New Democratic Party (NDP) from 2003 to 2011 and leader of the Official Opposition in 2011. He previously sat on Toronto City Council, occasionally holding the title of acting mayor or deputy mayor of Toronto during his tenure as city councillor. Layton was the member of Parliament (MP) for Toronto—Danforth from 2004 until his death.

The New Democratic Party is a federal political party in Canada. Widely described as social democratic, the party occupies the centre-left of the political spectrum, with the party generally sitting to the left of the Liberal Party. The party was founded in 1961 by the Co-operative Commonwealth Federation (CCF) and the Canadian Labour Congress (CLC).