Douglas Francis Warham "Frank" St. Leger (May 30, 1890 – December 26, 1969) was a British-American conductor of Indian birth.

St. Leger was born in Madras, now Chennai, India, to British parents.

At 16, he entered the Royal Academy of Music in London, where he studied piano and conducting.

He served in the Australian army for two years, following which he was appointed the pianist and conductor for the opera singer Dame Nellie Melba.

He remained at the Metropolitan for the following eleven years, holding subsequent positions as regular conductor, musical secretary, and company assistant manager in charge of repertory.