Frank Gruber (1904–1969) was an American writer of short stories, novels and screenplays, best known for Western and detective fiction.

After serving in the Army and working as an editor and correspondence-school teacher, he began selling pulp stories in the early 1930s. He created detective characters including Johnny Fletcher and Simon Lash and published dozens of Western novels. Gruber’s work moved from pulp magazines to Hollywood film and television. He wrote screenplays and more than 200 television scripts, and created the series Tales of Wells Fargo, The Texan and Shotgun Slade. His pen names included Stephen Acre, Charles K. Boston and John K. Vedder. He also wrote The Pulp Jungle, a memoir of the pulp-writing business.