Harry Corwin Nixon (April 1, 1891-October 22, 1961) was a Canadian politician and briefly Premier of Ontario.

He was first elected to the Ontario legislature in 1919 as a member of the United Farmers of Ontario and served as a Cabinet minister in the government of Premier Ernest C. Drury as Provincial Secretary and Registrar. Following the defeat of the UFO-Labour government in 1923, Nixon sat as a Progressive MPP becoming the leader of the small Progressive bloc (as most UFOers now called themselves) ater the 1929 Ontario election . Mitchell Hepburn, a farmer, became leader of the Ontario Liberal Party and Nixon led his Progressive remnant into an alliance with Hepburn's party. In 1934, Nixon and his followers ran as Liberal-Progressives helping bring the Hepburn to power in 1934. He ran again as a Liberal-Progressive in 1937.

Nixon resumed his old Cabinet position of Provincial Secretary and Registrar in the Hepburn cabinet and was the senior minister in the government. During World War II, Hepburn clashed with William Lyon Mackenzie King, the Liberal Prime Minister of Canada arguing that King was not sufficiently prosecuting the war effort, in particular by not introducing conscription (see Conscription Crisis of 1944). Hepburn openly supported King's rival, Conservative leader Arthur Meighen in a 1942 York South by-election and seemed to be calling for the defeat of King. This was too much for many Ontario Liberals who were either King loyalists or feared a rift betweent the federal and provincial parties. Hepburn was forced to resign on October 21 1942. Nixon was widely seen as the heir apparent and had earlier turned down Hepburn's offer to appoint him Premier as Nixon insisted the leadership should be the choice of the party, not of Hepburn. However, Hepburn, while resigning as Premier, insisted on remaining as party leader and simply appointed his ally, Gordon Daniel Conant as the new Premier of Ontario on October 21 1942. Nixon resigned from the cabinet on October 22, 1942 in opposition to Hepburn's decision to unilaterally appoint a new Premier rather than allow a leadership convention. Conant was forced to resign after only six months due to serious divisions in the party and a leadership convention was called. Nixon was chosen as Liberal leader and Premier in May 1943 but his government was unable to win the election held three months later and the Liberals were reduced to third place behind George Drew's Progressive Conservatives and Ted Jolliffe's CCF

Harry Nixon remained a Liberal MPP until his death in 1961. His son, Robert Nixon succeed him as MPP and later became leader of the Liberal Party but never Premier. He served as Treasurer in the Cabinet of David Peterson from 1985-1990. Harry Nixon's granddaughter (and Robert Nixon's daughter) Jane Stewart served as a Cabinet minister in the federal Liberal government of Jean Chrétien.