'GC' was the designation of Allied convoys (together with a numerical suffix) plying the route from Gibraltar to Casablanca, Morocco, and inaugurated in November 1942 after the success of 'Torch' with the original designation 'TF', and as such reciprocals of the 'CG' series (March 1943/April 1945).

The first known member of the series was GC.3 of 5/6 March 1943 with eight ships, and the last was GC.133 of 3/4 April 1945 with the 4,151-ton Greek Agia Marina, 7,009-ton British Empire Spartan and 7,219-ton British Samuta.