Anorexia nervosa (AN) is a complex and life-threatening eating disorder. Current models of AN onset and maintenance have largely focused on the role of negative affect, while fewer models have described the role of positive affect (PA). Given that these theoretical models have informed current treatment approaches, and that treatment remains minimally effective for adults with AN, we advocate that targeting PA is one avenue for advancing maintenance models and by extension, treatment. We specifically propose that AN may arise and be chronically and pervasively maintained as a function of dysregulated PA in response to weight loss and weight loss behaviors (e.g., restriction, excessive exercise), to a degree that is not accounted for in existing models of AN. We present evidence from multiple domains, including biological, behavioral, and self-report, supporting the hypothesis that PA dysregulation in AN contributes to the maintenance of the disorder. We conclude with several specific avenues for treatment development research as well as a call for future work elucidating the biological correlates of PA.