Mark Leier is a Canadian historian and, since 1994, a professor of working class and left-wing history at Simon Fraser University (SFU). From 2000 to 2010, he was the director of the Centre for Labour Studies at Simon Fraser.

Leier was born in Ladner, British Columbia. Prior to attending university, Leier was employed in various professions, including as a union carpenter and as a member of the Canadian Union of Public Employees. He earned his PhD in History from Memorial University of Newfoundland (MUN) in 1992.^[1]

Politically anarchist, Leier's books have mostly reflected on British Columbia's history of labour radicalism. His first book, Where the Fraser River Flows: The Industrial Workers of the World in British Columbia (1990) deals with the development of industrial unionism in the province. Red Flags and Red Tape: The Making of a Labour Bureaucracy (University of Toronto Press) deals with the institutionalization of a non-revolutionary labour movement. In Rebel Life: The Life and Times of Robert Gosden, Revolutionary, Mystic, Labour Spy (1999), Leier examines the life of an Industrial Workers of the World member (or "Wobbly") turned police labour spy. His fourth book, Bakunin: The Creative Passion is a political biography of the 19th-century Russian anarchist, Mikhail Bakunin.

As part of the Graphic History Collective, he helped produce May Day: A Graphic History of Protest.^[2]

A former folk singer, Leier is also known for bringing a banjo to his history classes.^[3]