Marshall Glecker Holloway (November 23, 1912 – June 18, 1991) was an American physicist who worked at the Los Alamos Laboratory during and after World War II. He was its representative, and the deputy scientific director, at the Operation Crossroads nuclear tests at Bikini Atoll in the Pacific in July 1946. Holloway became the head of the Laboratory's W Division, responsible for new weapons development.