Joanna Jędrzejczyk (Polish: (listen) (YEND-JY-CHICK); born August 18, 1987) is a Polish mixed martial artist and former Muay Thai kickboxer who competes in the women's flyweight and women's strawweight division of the Ultimate Fighting Championship (UFC). She is a former UFC Women's Strawweight Champion. As of February 10, 2020, she is #4 in the UFC women's strawweight rankings and #5 in UFC women's pound-for-pound rankings.
Jędrzejczyk discovered Muay Thai when she was 16, while taking up fitness, which eventually led her to compete in national and European tournaments. Jędrzejczyk competed in Muay Thai and kickboxing for 10 years, winning over 60 matches. Her amateur Muay Thai accomplishments include six IFMA world medals (five gold, one silver) and four IFMA Eurpopean championships with a record of 37 wins and 3 losses. During her professional career Jędrzejczyk won five world titles including the WKN World Championship, J Girls Championship, WBKF Championship, WKF European Championship, and the WMC Championship. Her professional record is 27–3.