Murphy, representing team Alvarez, was seeded third and therefore was automatically set to fight fourteenth seed Nicco Montaño. She lost the fight via Unanimous Decision in two rounds, eliminating her from the competition. Later, feeling discontent with her training on Team Alvarez (especially with Alvarez), she switched teams to Gaethje. Murphy was scheduled to face Priscila Cachoeira on December 1, 2017 at . However, due to a visa issue, the fight was cancelled and Murphy was asked to be ready to fight as an alternate. With Roxanne Modafferi elevated to the main event to fight Nicco Montaño after Sijara Eubanks was medically disqualified from the title fight, Murphy stepped in to face Barb Honchak. Murphy won the back-and-forth fight by split decision. Murphy faced Sijara Eubanks at on June 1, 2018. She lost the fight via unanimous decision. Murphy was scheduled to face Ashlee Evans-Smith on February 17, 2019 at UFC on ESPN 1. However on December 19, 2018 Murphy announced and withdraw from the event as she would need more time off to recover from foot surgery. Murphy faced Mara Romero Borella on August 3, 2019 at UFC on ESPN 5. She won the fight via TKO in the third round. Murphy faced Andrea Lee on February 8, 2020 at UFC 247. She won the fight via controversial split decision. 12 out of 12 MMA media outlets scored the contest for Lee with none scoring it for Murphy,  despite Murphy achieving a higher degree of accuracy and securing the only two takedowns in the fight. Murphy faced Roxanne Modafferi on June 20, 2020 at . She won the fight by unanimous decision.