Franklin Walter Olin (January 9, 1860 – May 21, 1951) was an American industrialist, philanthropist, and professional baseball player.

Olin studied civil engineering at Cornell University, entering in 1881, where he also played baseball.

While at Cornell, Olin was a well-regarded student athlete; he played both outfield and second base for the varsity baseball team, served as captain of the rifle team, rowed with the crew, and set school records in shot put and hammer throw.

His management of the several inter-related businesses has been described as "autocratic," characterized by close personal management of the enterprise and a fairly secretive attitude toward sales information and trade secrets, due especially to the businesses' rivalry with DuPont.

A portion of his fortune was willed to the Franklin W. Olin Foundation, which endowed numerous buildings and professorships in his name at college campuses across the United States.