Résumé : This contribution reports on the results of an uncontrolled longitudinal study investigating the effects of a Multi-Family Therapy (MFT) as treatment for adolescent Anorexia Nervosa (AN) and the role played by perceived family functioning in these effects. 150 patients (144 females) and their families took part in a MFT and were assessed at the beginning, middle, end of the therapy, as well as 6 and 12 months after the end of therapy. BMI, eating disorders symptomatology (EDI-II) and perceived family functioning (FAD) all improved over the time of MFT, and these benefits remained at both times of follow-up. Ultimately, we found that the improvement of some dimensions of family functioning (i.e., roles, communication, and general family functioning) mediated the improvement of several dimensions of symptomatology (i.e., ineffectiveness, impulsivity, social insecurity, interpersonal distrust). These observations provide further support for MFT as useful for improving mental health, weight restoration and perceived family functioning of adolescents with AN.