Grand Touring Over (GTO) is the name of a former classification designated to grand touring cars competing in sports car racing, originally by IMSA in the IMSA GT Championship, and later by Grand-Am in the Rolex Sports Car Series. IMSA used the class between 1971 and 1991, and Grand-Am used the class for a single season in 2000. The class had its origins in the original "TO" class used by the SCCA in the Trans-Am series, and was also similarly modeled to the FIA's Group 4 and Group 5 racing classes, but eventually evolved over time into its own category.
Grand Touring Over (GTO) was a classification used for high-performance sports cars competing in racing events, initially by IMSA in their GT Championship and later by Grand-Am in the Rolex Sports Car Series. The class originated from the SCCA's "TO" class in the Trans-Am series and was modeled after FIA's Group 4 and Group 5 classes.