O6

O6 or O-6 may refer to:

• LNER Class O6, a class of British steam locomotives
• O6 star, a subclass of O-class stars
• OceanAir IATA airline designator
• O-6, a pay grade in the US uniformed services:
  • Colonel in the Army, Marine Corps, Air Force, and Space Force
  • Captain in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps
• the "Occupied 6", an Irish republican euphemism for Northern Ireland
• USS O-6 (SS-67), an O-class submarine of the United States Navy
• Otoyol 6, a motorway in Turkey

See also

• 06 (disambiguation)
• 6O (disambiguation)