Joseph Philippe Baby Casgrain (March 1, 1856 – January 6, 1939) was a Quebec surveyor, civil engineer and political figure.

He was a Liberal member of the Senate of Canada for De Lanaudière division from 1900 to 1939.

He was born at Quebec City in 1856, the son of Philippe Baby Casgrain, and studied at the Séminaire de Québec.

He later became chief engineer for the Montreal and Pacific Junction Railway, also serving as a director for the company.

In 1885, he married Ella, the daughter of lumber merchant James William Cook.