Oscar Drouin (September 29, 1890 – July 16, 1953) was a politician in Quebec, Canada.^[1]

He was born on September 29, 1890, in Quebec City.

Drouin won a by-election in 1928 and became the Liberal Member of the Legislative Assembly of Quebec for the district of Québec-Est. He was re-elected in the 1931 general election.

He joined the newly formed Action libérale nationale (ALN) in 1934 and was re-elected as a candidate of that party in the 1935 election.

After the ALN merged with the Conservative Party to form the Union Nationale, Drouin became Maurice Duplessis's campaign manager. He won re-election in the 1936 election and Duplessis became Premier.

Drouin was a mayoral candidate in Quebec City in 1934. He was defeated by Joseph-Ernest Grégoire.

Drouin was appointed to the Cabinet. He became the Minister of Lands and Forests, but resigned in 1937. He and colleagues René Chaloult, Joseph-Ernest Grégoire, Philippe Hamel and Adolphe Marcoux left the Union Nationale.^[2] Drouin eventually switched Liberal and was re-elected in the 1939 election. He served as Minister of Municipal Affairs in Premier Adélard Godbout's Cabinet.

Drouin did not run for re-election in the 1944 election. He was succeeded by his brother Henri-Paul. He ran as an Independent candidate in the federal district of Matapédia—Matane in the 1945 federal election, but lost.

Drouin died on July 16, 1953.