This page is a list of British army-level formations existing during the First World War.

This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (November 2020)

This article relies largely or entirely on a single source. (November 2020)

• British Expeditionary Force (BEF)
  • First Army
  • Second Army
  • Third Army
  • Fourth Army
  • Fifth Army (originally the Reserve Army)
• Mediterranean Expeditionary Force (MEF)
  • Dardanelles Army
  • Egyptian Expeditionary Force (EEF)
  • British Salonika Army (BSF)
• Mesopotamian Expeditionary Force
• British Force in Italy

• Central Force
  • First Army
  • Second Army
  • Third Army
• Northern Army
• Southern Army

• Maj A.F. Becke,History of the Great War: Order of Battle of Divisions, Part 4: The Army Council, GHQs, Armies, and Corps 1914–1918, London: HM Stationery Office, 1944/Uckfield: Naval & Military Press, 2007, ISBN 1-847347-43-6.