'SQ' was the designation of Allied convoys (together with a numerical suffix) plying the route from Sydney, Nova Scotia, to Quebec, Canada, and as such reciprocals of the 'QS' series (May 1942/November 1944).

The first of the 96 such convoys was SQ.1 of 17 May 1942 with the 1,789-ton British Connector, and the last was SQ.106 of 19/21 November 1944 with the 4,155-ton British Blairnevis, 7,068-ton British Empire Pickwick, 7,244-ton Norwegian Kronprincessen, 2,373-ton British Nipiwan Park and 7,199-ton British Point Pelee Park.