A Machine Gun Company, of the Canadian Machine Gun Corps, was attached to each Canadian Infantry Brigade, until the formation of Canadian MG Battalions.
The 15th C.M.G. Coy. was the Divisional Reserve MG Company, 3rd Canadian Infantry Division.
It was assembled on 18 January, 1917, at Floringhem, near Pernes-des-Artois. The personnel were drawn from the existing Machine Gun Companies, Infantry Battalions in the field, and the Depot.
On 23 March, 1918, whilst still holding the Mericourt-Avion line, it was amalgamated with the 9th C.M.G. Company to form No. 2 Company, 3rd Bn, C.M.G.C..