155th (Mixed) Heavy Anti-Aircraft Regiment was an air defence unit of Britain's Royal Artillery formed during World War II. Around two-thirds of its personnel were women from the Auxiliary Territorial Service (ATS). After defending the West of Scotland and later London, the regiment was heavily engaged in Operation Diver against V-1 flying bombs, and later was deployed to Antwerp to carry out anti-Diver duties there in the closing stages of the war.