3 Squadron or 3rd Squadron may refer to:
Aviation squadrons No. 3 Squadron RAF No. 3 Squadron RAAF No. 3 Squadron RCAF No. 3 Squadron RNZAF No. 3 Squadron, Indian Air Force No. 3 Squadron RAF Regiment, a British field squadron 3rd Air Squadron, Indonesia 3rd Tactical Squadron, Poland 3rd Tactical Fighter Squadron (JASDF), Japan 3rd Squadron (Iraq)
United States 3rd Airlift Squadron 3rd Fighter Training Squadron 3rd Special Operations Squadron 3rd Weather Squadron
Naval squadrons 3rd Battle Squadron, Royal Navy 3rd Battlecruiser Squadron, Royal Navy
See also 3rd Wing