The first Marine Fixed Wing Observation 155 (VMO-155) squadron was commissioned at MCAS Quantico on July 27, 1943. That November VMO-155 was moved to San Diego and on January 1, 1944 it was redesignated VMO-1 and deployed to Espiritu Santo. In February 1944 the squadron redeployed to Guadalcanal and ultimately participated in the Battle of Guam. In February and March 1945 the squadron participated in the Battle of Iwo Jima.

On November 1, 1943 VMO-251 was commissioned at MCAS Quantico. In February 1944 the squadron was redesignated VMO-2 and transferred to the Second Marine Division in Hawaii flying the OY-1 aircraft. The squadron participated in the Battle of Saipan and the Battle of Tinian. The Battle of Okinawa would be the last action for the squadron in World War II.

VMO-2 was decommissioned on August 26 1946.

On June 15 1951 the squadron was recommissioned at MCAS Santa Ana.

In 1953 the squadron received the Cessna OE-2. In 1958 the squadron participated in the intervention in Lebanon and, in 1965, the Dominican Republic.

In 1968 VMO-1 and VMO-2 both received the OV-10 “Bronco” and were involved in extensive operations in the Republic of Vietnam.

In the mid-1980s VMO-1 participated in the “Vice President’s Joint Task Force for Drug Interdiction” conducting detection and interdiction flights in collaboration with Customs, the DEA, the U.S. Navy, the U. S. Air Force as well as state and local agencies throughout the Caribbean.

In December 1990 VMO-1 boarded the USS America and the USS Theodore Roosevelt and embarked to Saudi Arabia. In Operation Desert Storm the squadron flew over 1,000 combat sorties.

VMO-2 flew six aircraft on an unprecedented 10,000 mile flight to Saudi Arabia in support of Operation Desert Shield. VMO-2 flew 286 combat sorties in support of Operation Desert Storm.

Both squadrons were deactivated on July 31, 1993.