James Lesslie (November 22, 1802 – April 19, 1885) was an Ontario bookseller, reform politician and newspaper publisher. His career was closely associated with - and somewhat overshadowed by - William Lyon Mackenzie, the Reform agitator, mayor of Toronto, and Rebellion leader. However, as a leader himself, Lesslie took a prominent role in founding the Mechanics Institute (for adult education), the House of Refuge & Industry (a shelter for the unemployed), the Bank of the People, as well as the political parties known as the Canadian Alliance Society and Clear Grits. In many way, he defined the Reform movement in Upper Canada without having reverted to the violent methods of Mackenzie. His legacy may thus have lasted longer.