O9

O9 or O-9 may refer to:

• , an O-class submarine of the United States Navy
• O-9, the pay grade for the following senior officer ranks in the U.S. uniformed services:
• Lieutenant General in the Army, Marine Corps, Air Force, and Space Force
• Vice Admiral in the Navy, Coast Guard, Public Health Service Commissioned Corps, and NOAA Commissioned Officer Corps
• Douglas O-9, a variant of the Douglas O-2, a 1920s American observation aircraft
• O9 (model railways), a narrow-gauge model railway scale
• Oregon-IX (OIX), an internet exchange; see List of Internet exchange points

See also

• 09 (disambiguation)
• 9O (disambiguation)
• oix (disambiguation)