Anorexia nervosa (AN) is a debilitating and often chronic and treatment-resistant disorder. Despite decades of theoretical progress and research, many questions remain with regard to the psychological mechanisms explaining why and how some AN patients respond to treatment whereas others do not. Based on the premise that the broader, noneating disorders psychotherapy research literature, and particularly the common factors literature, can inform AN treatment development efforts, we review a set of selected psychological change mechanisms and describe how they might be relevant in the context of AN treatment response. Specifically, we suggest that a systematic consideration of constructs such as basic psychological needs, expectancies, the therapeutic alliance, experiential avoidance, and patient motivation for change might help illuminate how patients do or do not benefit from AN treatment. We briefly describe an ongoing multicenter trial in which the constructs introduced here are being measured on a weekly basis and are examined as potential mediators of treatment response. The article aims to contribute to the AN literature by introducing a set of potentially important change constructs that we think ought to be studied in greater depth by AN researchers.