Mackenzie Lynne Dern is an American and Brazilian professional mixed martial artist and Brazilian Jiu-Jitsu practitioner currently competing in the women's strawweight division of the Ultimate Fighting Championship (UFC), where she is the current UFC Women's Strawweight Champion. She is a former world no. 1 ranked IBJJF competitor, currently ranked 6th among the female divisions. She is an ADCC and no gi BJJ world champion. As of August 18, 2026, she is #5 in the UFC women's pound-for-pound rankings.