O15

O15 may refer to:
 * HNLMS O 15, a submarine of the Royal Netherlands Navy
 * Keystone O-15, a prototype aircraft built for the United States Army Air Corps
 * Oxygen-15, an isotope of oxygen
 * Turlock Municipal Airport, in Merced County, California, United States
 * USS O-15 (SS-76), a submarine of the United States Navy