O5

O5 or O-5 may refer to:

• The Outreach Five a.k.a "Group of Five", emerging economies in the G8+5 forum: China, Mexico, India, Brazil and South Africa
• A symbol for the anti-Nazi Austrian Resistance, where the 5 stands for E and OE is the abbreviation of Österreich
• USS O-5 (SS-66), a 1917 O-class submarine
• HNLMS O 5, a 1913 O 2 class submarine of the Royal Netherlands Navy
• SM UC-99, a U-boat renamed O-5 for Japanese service from 1920 to 1921
• Douglas World Cruiser, also designated as Douglas O-5
• De Havilland Canada Dash 7, also designated as De Havilland Canada O-5
• LNER sub-class O4/5, a subclass of the LNER Class O4, locomotive class
• O-5, the pay grade for the following officer ranks in the U.S. uniformed services:
  • Lieutenant colonel in the Army, Marine Corps, Air Force, and Space Force
  • Commander in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps
• Otoyol 5, a toll motorway in Turkey
• The time-displaced X-Men, also called "The Original 5"
• The senior “overseer” position in the fictional SCP Foundation

See also

• 5O (disambiguation)
• Five-O (disambiguation)
• 05 (disambiguation), zero five