Direct proof of use
The Su-25 is documented in the 1990 Gulf War as an Iraqi ground-attack aircraft. AirVectors lists Iraq among Su-25K export operators and describes Iraqi Su-25Ks as having Gulf War service, mostly as aircraft hit by coalition airstrikes on runways or hardened shelters and as aircraft flown to Iran.
Air Force Historical Research Agency reporting on the Iraqi Air Force records two Su-25s among Iraqi fixed-wing aircraft shot down by USAF pilots during Operation Desert Storm. The same study says coalition operations destroyed large numbers of Iraqi aircraft on the ground and that 121 Iraqi fixed-wing combat aircraft were flown to Iran and never returned.
Sources: Sukhoi Su-25 Frogfoot, What Happened to the Iraqi Air Force
Campaign chronology
Open operational histories describe at least one Iraqi Su-25 squadron as seeing action during the August 1990 invasion of Kuwait, but detailed public sourcing for individual Su-25 strike sorties is limited. During the January-February 1991 air campaign, the better-documented Su-25 events are losses, dispersal, and evacuation rather than sustained attack operations.
On February 6, 1991, two Iraqi Su-25s were reported shot down by U.S. F-15C interceptors with AIM-9 Sidewinder missiles. After the air campaign and ground offensive, public-domain imagery from Jalibah Air Base dated March 3, 1991 recorded a destroyed Iraqi Su-25 from Operation Desert Storm.
Sources: Operational history of the Sukhoi Su-25, What Happened to the Iraqi Air Force, NARA Destroyed Iraqi Su-25
Operational role
The Su-25's Gulf War role was tied to Iraq's ground-attack aviation, not to coalition air operations. In catalog terms, the documented side is Iraqi government and security forces, and the aircraft belongs with close air support, battlefield strike, and interdiction roles.
The aircraft's practical wartime record was constrained by the wider collapse of Iraqi air operations. Air Force history says Iraqi pilots became reluctant to engage coalition aircraft, coalition forces shifted from runway attacks to aircraft shelters and dispersed aircraft, and Iraq then sought to preserve aircraft by flying them to Iran. AirVectors states that Iraqi Su-25s were among the combat aircraft flown to Iran, and later notes that seven Su-25s supplied back from Iran to Iraq in 2014 were former Iraqi machines that had fled during the First Gulf War.
A public-domain image of a destroyed Iraqi Su-25 at Jalibah Air Base illustrates the ground-loss side of the record. It supports the conclusion that the Su-25 was present in the theater and was caught in the same airfield-suppression campaign that reduced Iraq's fixed-wing force during Operation Desert Storm.
Sources: Sukhoi Su-25 Frogfoot, What Happened to the Iraqi Air Force, NARA Destroyed Iraqi Su-25