The 1975 championship was one of the most controversial in the history of the title with series leader Allan Grice disqualified from the fifth round at Surfers Paradise for a technical infringement. He continued racing under appeal, but the penalty was upheld and Grice lost all points gained from the final three rounds. Reigning champion Peter Brock parted company with the Holden Dealer Team before the series began and raced in a privately funded Holden Torana during the season. Colin Bond, driving a Holden Torana for the Marlboro Holden Dealer Team took victory at the opening round at Symmons Plains Raceway, and end of season wins at Adelaide International Raceway and Lakeside International Raceway saw Bond move past Grice and Bob Morris on points to win the championship. 2000cc class competitor Christine Gibson, driving a factory supported Alfa Romeo 2000 GTV, led the series mid-season after taking four class wins, but had disqualification problems of her own and Bond regained the points advantage by season's end. Gibson's effort however remains to this day (2012) the best performance by a woman in Australian Touring Car Championship history.
Championship points were awarded on a 9-6-4-3-2-1 basis for the first six positions in each class at each round. Bonus points were awarded on a 4-3-2-1 basis for the first four outright positions at each round.