Oliver T. Marsh (January 30, 1892 in Kansas City, Missouri, United States – May 5, 1941 in Hollywood, California, United States) was a prolific Hollywood cinematographer. He worked on over eighty films just for Metro-Goldwyn-Mayer alone.
Marsh worked on Sadie Thompson (1928), Rain (1932), The Merry Widow (1934), David Copperfield (1935), A Tale of Two Cities (1935), The Great Ziegfeld (1936), San Francisco (1936) and Another Thin Man (1939). He and Allen Davey received Academy Honorary Awards "for the color cinematography of the Metro-Goldwyn-Mayer production, Sweethearts" (1938) at the 11th Academy Awards. The pair were also nominated for Best Cinematography (Color) for Bitter Sweet (1940).
Marsh is interred at Forest Lawn Memorial Park in Glendale, California.
He is the brother of actresses Marguerite Marsh (1888–1925) and Mae Marsh (1894–1968), as well as editor Frances Marsh, and the father of jazz saxophonist Warne Marsh (1927–1987).