In military terms, 4 Squadron, IV Squadron or 4th Squadron may refer to:
Aviation squadrons :
- No. 4 Squadron RAAF, a unit of the Royal Australian Air Force
- No. 4 Squadron (India), a unit of the Union of India Air Force
- No. 4 Squadron RNZAF, a unit of the Royal New Zealand Air Force
- 4 Squadron SAAF, a unit of the South African Air Force
- No. IV Squadron RAF, a unit of the United Kingdom Royal Air Force
- 4th Aero Squadron, later 4th Squadron (Observation), 4th Observation Squadron, 4th Reconnaissance Squadron, a unit of the United States Air Corps
- 4th Fighter Squadron (United States), a unit of the United States Air Force
- 4th Space Control Squadron (United States), a unit of the United States Air Force
- 4th Space Operations Squadron (United States), a unit of the United States Air Force
- HS-4 (Helicopter Anti-Submarine Squadron 4), a unit of the United States Navy
- VMAQ-4 (Marine Tactical Electronic Warfare Squadron 4), a unit of the United States Marine Corps
Naval squadrons :
Ground combat squadrons :