The Japanese car maker had been considering its position after champions Porsche pulled out at the end of the 2017 season, leaving Toyota as the only major manufacturer in the top LMP1 category.
Toyota said in a statement on Tuesday, however, that it was committed to "at least" the 2018-19 season following publication of the regulations.
The 'super season' will last 14 months and includes two editions of the Le Mans 24 Hours sportscar race in June 2018 and 2019.
"It is highly regrettable that our rival in honing technologies on the roads of Le Mans has left," said Toyota president Akio Toyoda.
"Yet the World Endurance Championship ... and particularly Le Mans, where the battle goes on for 24 hours, including on public roads, still represent the optimal proving ground for achieving the goal of making cars fun for the next 100 years."
The decision is a boost for double Formula One world champion Fernando Alonso, who tested with Toyota in Bahrain last month and is eager to race at Le Mans in his bid to become only the second driver to win the "Triple Crown" of motorsport.
McLaren have ended their Formula One partnership with Honda, opening the door for Alonso to drive for Toyota at Le Mans — a race that does not clash with any grand prix.
Toyota said it will announce the world endurance driver lineup early next year.
Only one Japanese manufacturer has ever won Le Mans, Mazda in 1991. Toyota has been five-time runnerup and has spent hundreds of millions of dollars over the years in pursuit of victory at the French endurance classic.
Reporting by Alan Baldwin