There is emerging evidence suggesting atypical anorexia nervosa (AAN), an eating disorder (ED) introduced in the DSM-5, is as serious an ED as anorexia nervosa (AN) in terms of medical risk and ED pathology. Medical hospitalizations among individuals with AAN have significantly increased over the years and individuals with AAN are noted to have longer illness durations and greater weight loss prior to receiving care than individuals with AN. Additionally, AAN is noted to be two to three times more common than AN in community samples of adolescents. Given that AAN is a newer diagnosis, research knowledge and evidence-based treatment guidelines are emerging, yet pivotal. Thus, this article discusses specific considerations during assessment and treatment using Family Based Treatment (FBT) among adolescents diagnosed with AAN and clinical and ethical concerns involved while providing effective care and mitigating any weight bias or stigma related to historical and current weight status.