John Giles Lethbridge (August 13, 1855 – 1947) was an Ontario farmer and political figure.
He represented Middlesex West in the Legislative Assembly of Ontario from 1919 to 1929 as a United Farmers and then Progressive member.
He was appointed to Master and Secretary of the Dominion Grange, an agrarian advocacy organization.
[1] Following the resignation of William Raney, Lethbridge, at the age of 72, was elected leader of the Progressive Party on November 18, 1927, at a joint meeting of Progressive MPPs and the party executive.
[1] As leader, Lethbridge supported a strong temperance policy in opposition to the liberalization of liquor laws by the government of Howard Ferguson.