Kayla Jean Harrison[4] (born July 2, 1990) is an American professional mixed martial artist and former judoka.

Born in Middletown, Ohio,[6] Harrison took up judo at the age of six, having been introduced to the sport by her mother, who was a black belt.

[8] A month after the abuse was revealed, she moved away from her home in Ohio to Boston to train with Jimmy Pedro and his father.

[6] Harrison won the gold medal in the ‍–‍78 kg category at the 2010 World Championships,[9] the first American to do so since 1999 (when her coach, Jimmy Pedro, did so in Birmingham, United Kingdom).

[11] Prior to the 2012 Summer Olympics in London, Harrison was injured during training, having torn a medial collateral ligament.

[12][13] She earned a second Olympic gold medal in the same weight class in 2016 in Rio, defeating Audrey Tcheuméo of France.

In 2015, Harrison was elected to the United States Judo Federation Hall Of Fame[14] and on August 31, 2016, following her second Olympic gold medal, the United States Judo Association made a batsugun promotion of Harrison to rokudan (6th Degree Black Belt) making her the youngest person in the US to ever be awarded this rank.

Harrison, a former training partner of fellow judoka Ronda Rousey, announced in October 2016 that she had signed with World Series of Fighting.

[15][16] Harrison made her MMA debut at PFL 2 on June 21, 2018, against Brittney Elkin in the Women's Lightweight division.

[20] Harrison was on the main card for PFL 11 in 2018 and defeated Moriel Charneski via first-round TKO; after her victory, it appeared that she was not completely content with her own performance.

[32] After dominating every round with her superior grappling, Harrison won the fight by unanimous decision to win the 2019 Women's Lightweight Championship.

[48] Being one of the most sought-after free agents in the sport, Harrison ended up signing a contract with Bellator MMA in March 2022.

[54] Harrison faced Martina Jindrová in the Semifinals off the Women's Lightweight tournament on August 20, 2022, at PFL 9.

[56] Harrison faced Larissa Pacheco for a third time in the finals of the Women's Lightweight tournament on November 25, 2022, at PFL 10.

[59] However, Budd was removed from the fight that she "refused to fulfill her contractual obligation" and was replaced by Aspen Ladd at a catchweight of 150 pounds.