Robert Fletcher Nixon is a retired Canadian politician in the province of Ontario, Canada. The son of former Premier of Ontario Harry Nixon, he was first elected to the Legislative Assembly of Ontario in a 1962 by-election following his father's death. The younger Nixon was elected leader of the Ontario Liberal Party in 1967 and led them through three provincial elections, the first two where the Liberals retained their standing as the second-largest party and official opposition in the legislature.

Harry Corwin Nixon was a Canadian politician and briefly the 13th premier of Ontario in 1943. He is both the longest-serving member in the history of the Ontario legislature and the shortest-serving premier of Ontario.