USS Oriskany (CV/CVA-34) – nicknamed Mighty O, and occasionally referred to as the O-boat – was one of the few Essex-class aircraft carriers completed after World War II for the United States Navy. The ship was named for the Battle of Oriskany during the Revolutionary War.

The history of Oriskany differs considerably from that of her sister ships. Originally designed as a "long-hulled" Essex-class ship (considered by some authorities to be a separate class, the Ticonderoga class) her construction was suspended in 1946. She eventually was commissioned in 1950 after conversion to an updated design called SCB-27 ("27-Charlie"), which became the template for modernization of 14 other Essex-class ships. Oriskany was the final Essex-class ship completed.

She operated primarily in the Pacific into the 1970s, earning two battle stars for service in the Korean War, and ten for service in the Vietnam War. In 1966, one of the worst shipboard fires since World War II broke out on Oriskany when a magnesium flare was accidentally ignited; forty-four men died in the fire.

Oriskany's post-service history also differs considerably from that of her sister ships. Decommissioned in 1976, she was sold for scrap in 1995, but was repossessed in 1997 because nothing was being done. In 2004, it was decided to sink her as an artificial reef off the coast of Florida in the Gulf of Mexico. After much environmental review and remediation to remove toxic substances, she was carefully sunk in May 2006, settling in an upright position at a depth accessible to recreational divers. As of 2008, Oriskany is the largest vessel ever sunk to make a reef.