IROC XII was the twelfth year of IROC competition took place in 1988. It saw the use of the Chevrolet Camaro in all races, and continued the format introduced in IROC VIII. Race one took place on the Daytona International Speedway, race two took place at Riverside International Raceway, race three ran at Michigan International Speedway, and race four concluded the year at Watkins Glen International. Al Unser Jr. won his second championship and $211,900. The roster of drivers and final points standings were as follows:

Race results

Race One, Daytona International Speedway

Friday, February 12, 1988 (5) Indicates 5 bonus points added to normal race points scored for leading the most laps. (3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps (did not occur in this race so not awarded). (2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps (did not occur in this race so not awarded). Average speed: 186.239 mph Cautions: 1 Margin of victory: 2 cl Lead changes: 0

Race Two, Riverside International Raceway

Saturday, June 11, 1988 (5) Indicates 5 bonus points added to normal race points scored for leading the most laps. (3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps (2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps (did not occur in this race so not awarded). Average speed: 98.182 mph Cautions: 2 Margin of victory: 2 sec Lead changes: 1 Lap Leader Breakdown

Race Three, Michigan International Speedway

Saturday, August 6, 1988 (5) Indicates 5 bonus points added to normal race points scored for leading the most laps. (3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps (2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps (did not occur in this race so not awarded). Average speed: 159.432 mph Cautions: none Margin of victory: 0.78 sec Lead changes: 1 Lap Leader Breakdown

Race Four, Watkins Glen International

Saturday, August 13, 1988 (5) Indicates 5 bonus points added to normal race points scored for leading the most laps. (3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps (did not occur in this race so not awarded). (2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps (did not occur in this race so not awarded). Average speed: 110.924 mph Cautions: 3 Margin of victory: 1.58 sec Lead changes: 0