'GZ' was the designation of Allied convoys (together with a numerical and sometimes a literal suffix) plying the route from Guantánamo, Cuba, to the Panama Canal, and as such reciprocals of the 'ZG' series (August 1942/May 1945).

The first of the 140 such convoys was GZ.1 of 31 August/3 September 1942 with the 8,139-ton British Daronia, 5,011-ton US Dona Aniceta, 9,990-ton British Empire Trader, 7,191-ton US Francis L. Lee, 9,351-ton Norwegian Hoegh Hood, 3,908-ton Soviet Mikhurin, 9,925-ton Norwegian Solfonn and 7,191-ton US Theodore Foster but no escorts, and the last was GZ.139 of 14/17 May 1945 with the 1,819-ton US All America, 1,339-ton Norwegian Ravnefjell and US tank landing ship LST-546 but no escort.