The Japanese manufacturer said in a statement before this weekend's race at Le Mans' Sarthe circuit that it would continue in 2021 with a hybrid-powered prototype based on the GR Super Sport road car.
Defending champions Toyota will start on pole position on Saturday after sweeping the front row in qualifying for the third year in succession.
"This new era of competition is a fantastic opportunity to demonstrate our credentials not only as a race team against some of the best in the business, but also as a sportscar manufacturer," said Toyota Gazoo president Shigeki Tomoyama.
Track testing of the new car will begin next year.
British sportscar maker Aston Martin, which last won Le Mans in 1959, has already committed to entering two Valkyrie hypercars in the 2020-21 world endurance championship.
Toyota are the sole major car maker in the series this season.
(Reporting by Alan Baldwin in London, editing by Pritha Sarkar)
