21 Squadron or 21st Squadron may refer to:

• No. 21 Squadron RAAF, Royal Australian Air Force
• No. 21 Squadron (Finland), Finnish Air Force
• 21 Squadron SAAF, South African Air Force
• No. 21 Squadron RAF, United Kingdom Royal Air Force
• 21st Aeromedical Evacuation Squadron, United States Air Force
• 21st Airlift Squadron, United States Air Force
• 21st Bombardment Squadron, United States Air Force
• 21st Fighter Squadron, United States Air Force
• 21st Operational Weather Squadron, United States Air Force
• 21st Photographic Reconnaissance Squadron, United States Air Force
• 21st Pursuit Squadron, United States Army Air Force
• 21st Space Operations Squadron, United States Air Force
• 21st Special Operations Squadron, United States Air Force
• 21st Tactical Air Support Squadron, United States Air Force

• 21st Brigade (disambiguation)
• 21st Regiment (disambiguation)

Topics referred to by the same term

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