79th Searchlight Regiment (79th S/L Rgt) was an air defence unit of Britain's Royal Artillery during World War II.

The role of the S/L units was to track and illuminate raiders for the Heavy AA (HAA) guns of the Inner Artillery Zone (IAZ) and for the few available Royal Air Force Night fighters.

The number of raiders shot down steadily increased until mid-May 1941, when the Luftwaffe scaled down its attacks, now considered as the end of the Blitz.

On 23 January 1942 the regiment took over 342 S/L Bty from 35th (First Surrey Rifles) S/L Rgt which was due to convert to the light AA gun role.

As they crossed South East England these raids were met by intense AA fire and RAF night fighters, which scored an impressive number of 'kills' in conjunction with radar-controlled S/Ls.

[8][22] 79th Searchlight Rgt and its three batteries, 502, 503 and 504, began disbanding at Hatfield Peverel, near Chelmsford in Essex, on 10 December 1944, but the process was not completed until 10 May 1945, just after the end of the war in Europe.