The 51st (Highland) Searchlight Regiment, Royal Artillery was a Scottish unit of Britain's Territorial Army (TA) formed for air defence just before World War II. It later served as an anti-aircraft (AA) artillery unit in the North West Europe Campaign 1944–45, and continued in the postwar TA into the 1950s.

The 3rd Anti-Aircraft Division was an air defence formation of the Territorial Army, part of the British Army, created in the period of tension before the outbreak of the Second World War. It defended Scotland and Northern Ireland during the early part of the war.