The Denison smock was a coverall jacket issued to Special Operations Executive (SOE) agents, the Parachute Regiment, the Glider Pilot Regiment, Air Landing Regiments, Air Observation Post Squadrons, Commando units, and other Commonwealth airborne units, to wear over their Battle Dress uniform during the Second World War. The garment was also issued as standard to the scout and sniper platoons of line infantry battalions.

The smock was initially worn over the paratrooper's webbing equipment, but under his parachute pack and harness, as its primary purpose was to prevent the wearer's equipment from snagging while emplaned or during a jump. It was equally useful for camouflage and as a windproof garment that provided a method of carrying ammunition or equipment. Contemporary photographs show that airborne troops preferred to wear the smocks under their webbing once they had landed.