UFC on Fox 31: Lee vs. Iaquinta 2 was a mixed martial arts event produced by the Ultimate Fighting Championship that was held on December 15, 2018 at Fiserv Forum in Milwaukee, Wisconsin, United States. A lightweight rematch between former interim title challenger Kevin Lee and Al Iaquinta served as the event headliner. The pairing met previously in February 2014 at UFC 169 with Iaquinta winning the fight via unanimous decision.