Maurice Janet (1888–1983) was a French mathematician.
In 1912 as a student he visited Göttingen. He was a professor at the University of Caen. He was an Invited Speaker of the ICM in 1924 in Toronto, in 1932 in Zürich, and in 1936 in Oslo.
Named in his honor are Janet bases, Janet sequences and a related algorithm in the theory of systems of partial differential equations. In 1926 he proved results that were later generalized in Nash's embedding theorem.
In 1948 he was the president of the Société Mathématique de France.
He was a close friend of the mathematician Ernest Vessiot.