Mezue ahịrịokwu na-esonụ: 21st Army Group bụ World War II British isi ụlọ ọrụ nhazi, na iwu nke abụọ ubi agha na ndị ọzọ na-akwado nkeji, esịnede tumadi nke British Nke abụọ Army na mbụ Canadian Army. E guzobere ya na London n'ọnwa Julaị nke afọ 1943, n'okpuru iwu nke Supreme Headquarters Allied Expeditionary Force (SHAEF), e kenyere ya na Operation Overlord,
Ndị Western Allied wakporo Europe, ma bụrụkwa ndị agha dị mkpa nke ndị Allied na European Theatre. N'oge dị iche iche n'oge ịdị adị ya, ndị agha nke 21 nwere ndị agha Britain, Canada, America na Polish ndị agha ma ọ bụ ndị agha jikọtara ya. 21st Army Group rụrụ ọrụ na Northern France, Luxembourg, Belgium, Netherlands na Germany site na June 1944 ruo August 1945, mgbe a kpọrọ ya British Army of the Rhine (BAOR).