2021 Super Taikyu Series

The 2021 Super Taikyu Series Powered by Hankook was the thirty-first season of the Super Taikyu Series endurance racing championship. It began on 21 March at Twin Ring Motegi and ended on 14 November at Okayama International Circuit.

D'station Racing won the championship in the series' GT3 category, known as ST-X, with an Aston Martin Vantage AMR GT3.

This was the first season for the new ST-Q class, introduced for manufacturer-developed, non-homolgated special racing vehicles. In this class, Toyota and ROOKIE Racing introduced the Toyota Corolla H2 Concept, a hydrogen internal combustion engine vehicle based upon the Toyota Corolla Sport hatchback. This car made its racing debut at the Fuji SUPER TEC 24 Hours. Mazda debuted the Mazda Demio Bio Concept in the final round at Okayama, which ran on renewable biodiesel fuel.

Calendar
A provisional calendar was announced on 20 November 2020, featuring six rounds at six Japanese motor racing circuits. Twin Ring Motegi moved back to the first round of the championship in March. Following the cancellation of the 2020 round at Suzuka Circuit, its date was moved to September and became the fifth round of the season.

The Fuji 24 Hours was moved from its original dates of 5-6 June to 22-23 May, in order to avoid a clash with 24 Hours of Le Mans test day and the 24 Hours of Nürburgring.

Teams and drivers
64 cars entered throughout the course of the 2021 season. All entries were registered under a Japanese license.

Championship standings
Championship points were awarded in every class with the exception of ST-Q at the end of each event. Each team's five highest-scoring rounds counted towards the final championship standings.