Léon Casgrain (August 13, 1892 – November 5, 1967) was a Canadian politician and jurist from Quebec.

He ran as a Liberal candidate in 1927 for the district of Témiscouata and won.

Casgrain was defeated in 1948 against Union Nationale candidate Roméo Gagné.

He became Minister without Portfolio in 1939 and served as the province's Attorney General from 1942 to 1944.

In 1948, he was appointed a puisne judge of the Superior Court of Quebec, retiring in 1967.