The third year of IROC competition took place over three weekends in 1975 and 1976. IROC III saw the use of the Chevrolet Camaro in all races, and the schedule was held over in its entirety from IROC II. A. J. Foyt won the championship without winning a race, and took home $50,000 for his efforts.
The roster of drivers and final points standings were as follows: