Formed at Catterick, North Yorkshire, on 1 January 1918 as a heavy night bomber unit, No. 118 Squadron never saw service in World War I and was disbanded again on 7 September 1918.
On 20 February 1941, No. 118 reformed at RAF Filton, near Bristol, as a No. 10 Group fighter squadron equipped with Spitfires. On 28 March, convoy patrols began and in June the Squadron began to provide bomber escorts and took part in fighter sweeps over northern France. In January 1943, it moved to East Anglia and began sweeps over the Netherlands, moving in September to northern Scotland on defensive duties. In January 1944 the Squadron came south again to join Second TAF but returned to the Orkneys in March for four months. Sweeps and bomber escort missions were resumed in July 1944 and in January 1945, the Squadron converted to Mustangs for long-range escort duties. These began on 1 February and continued to 3 May 1945. On 10 March 1946, the Squadron was disbanded.
On 10 May 1951, No. 118 reformed at RAF Fassberg as a Vampire fighter-bomber Squadron, re-equipping with Venoms in November 1953, and then becoming a day fighter unit when it was equipped with Hunters in May 1955, disbanding on 22 August 1957. On 1 September 1959, the Sycamore Flight of No. 228 Squadron at RAF Aldergrove became No. 118 Squadron in Transport Command. On 31 August 1962, the Squadron was disbanded.