15th Anti-Aircraft Brigade (15th AA Bde) was an air defence formation of the Royal Artillery which saw service during the middle years of the Second World War.

The brigade was formed in Gibraltar to control those anti-aircraft (AA) units based there and disbanded shortly after the air threat had been diminished in 1944.

Apart from occasional shots fired at unidentified aircraft penetrating Gibraltar's airspace, there were no attacks on the fortress during the 'Phoney War' period.

A searchlight battery arrived, and an AA Operations Room (AAOR) was established to control all the gunsites and to coordinate with AA-equipped ships in the harbour.

Equally important was the careful distribution of gun and radar positions to ensure the most effective converge from the increased firepower and the constant practice of day and night barrages, in which live firing was regularly employed and closely recorded, to eliminate errors and weak spots.

The basis of the plan for the revised layer was to bring the fire of 20 HAA guns to bear on a target travelling at 240 mph, approaching from any direction and at a typical height of 12,000 feet.

Part of this request was due to 15th AA Brigade's wish to provide the North airfield with its own LAA defence; hitherto it had depended on the main layout for coverage.

[18][19] The brigade's organisation was now as follows:[19] The 1947 plan was never fully implemented, and most of the Regular units assigned to AA Command were disbanded as part of postwar demobilisation.

As the Cold War developed, there was a need for new weapons, leading to the rise of surface-to-air missiles and 'blind fire' radar control, with the consequent decline of HAA guns and searchlights.