Mikaela Joslin Mayer (born July 4, 1990) is an American professional boxer who has held the WBO female super featherweight title since 2020. As an amateur she won a bronze medal at the 2012 World Championships and competed for the U.S. at the 2016 Olympics. As of February 2021, she is ranked as the world's second best active female super featherweight by BoxRec and third by "The Ring", as well as the tenth best active female, pound for pound, by "The Ring".