2021 GT World Challenge AmericaPrevious2020Next2022Pirelli GT4 America SeriesTC America SeriesGT America SeriesIndianapolis 8 Hours The 2021 GT World Challenge America Powered by AWS was the 15th season of the United States Auto Club's GT World Challenge America, and the fourth under ownership of SRO Motorsports Group.The season began at Sonoma on March 6, and ended at Indianapolis on October 17.