Lieutenant Commander Hamish Ian Mackintosh MBE (26 July 1940 — disappeared 7 July 1979) was a Scottish Royal Navy officer, a writer of thriller novels, and a screenwriter for British television.

Mackintosh's first novel, A Slaying in September, was published in 1967. He wrote four other original novels between 1967 and 1970; his later books were either based on his television series or were novelisations of episodes of his television series.