2021 in Bellator MMA was the thirteenth year in the history of Bellator MMA, a mixed martial arts promotion based in the United States. Bellator held 18 events in 2021.
The promotion went on a hiatus following Bellator 254 on December 10, 2020, which would be the final card to air on CBS Sports Network. Beginning in April, Bellator's U.S broadcasts moved to the premium Showtime network. Bellator 255, which took place on April 2, 2021, was the promotion's debut on Showtime, and the first MMA card to air on the network in over eight years; the last event being on January 12, 2013.