Joanna Jędrzejczyk (Polish: [jɔˈanna jɛnˈdʐɛjt͡ʂɨk]; born August 18, 1987) is a Polish mixed martial artist and former Muay Thai kickboxer who competes in the women’s flyweight division of the Ultimate Fighting Championship (UFC). She is a former UFC Women’s Strawweight Champion and the third European (and only Polish) champion in UFC history after Bas Rutten in 1999 and Andrei Arlovski in 2005. Prior to her defeat to Rose Namajunas, she was the #1 pound-for-pound female MMA fighter in the world. As of December 18, 2018, she is ranked #4 in the official flyweight rankings.
Due to her surname being difficult to pronounce for English speakers, fans and the media have given her unofficial nicknames, such as “Joanna Champion”, “Joanna Violence” or simply “Joanna”.