The 116th Light Anti-Aircraft Regiment (116th LAA Rgt) was a Welsh mobile air defence unit of the British Army's Royal Artillery (RA) during World War II.

116th LAA Regiment was formed in January 1942 by converting the 12th Battalion, Royal Welch Fusiliers, a war service infantry unit that had been raised in 1940 as part of the rapid wartime expansion of the British Army.

Training was hampered by the shortage of rifles and equipment, and the tented camp became uninhabitable during winter gales, with the battalions having to go into billets.

[6] 12th Royal Welch Fusiliers was converted into a light anti-aircraft (LAA) regiment of the RA, which officially came into existence on 1 January 1942.

[8] 53rd (Welsh) Division came under the command of XII Corps, and both were later assigned to 21st Army Group training for the Allied invasion of Normandy (Operation Overlord).

The division played a minor part in the next offensive phase, Operation Jupiter, guarding the western flank of the attack.

LAA units fired tracer to guide night attacks onto their objectives, and the Bofors guns were much in demand for infantry support.

[8][20] After the Falaise Pocket was eliminated, XII and XXX Corps led 21st Army Group's rapid advance eastwards to the Seine.

By then, 21st Army Group was suffering an acute manpower crisis, particularly among the infantry, and surplus units and formations were being disbanded to provide drafts.