["European Eating Disorders Review, EarlyView. ", "\nABSTRACT\n\nObjective\nThis study examined the effects of multi‐family therapy (MFT‐AN); delivered as 10 treatment days over one year; on weight, eating disorder behaviours and emotional problems in adolescents with anorexia nervosa. The added benefit of a 1‐year duration compared to 6 months was evaluated. Finally, the outcomes between stand‐alone MFT‐AN and MFT‐AN combined with inpatient treatment were compared.\n\n\nMethod\nSelf‐reported data from 230 adolescents (aged 9–18 years) and their families were collected at baseline (T0), 6 months (T6), and 12 months (T12). Percentage median BMI was calculated at all time points. Data were analysed using (generalised) linear mixed models.\n\n\nResults\nSignificant improvements were observed in percentage median BMI, anorectic symptoms and parent‐reported emotional problems, from T0 to T6 and T12 (p < 0.001) and from T6 to T12 (p = 0.002–p = 0.014). Ineffectiveness, body dissatisfaction, interoceptive awareness and drive for thinness (p < 0.001), fear of adulthood (p = 0.003) and perfectionism (p = 0.04) showed a significant improvement from T0 to T6 and T12, and from T6 to T12 (p = 0.008–p = 0.021). Interpersonal distrust showed only a significant improvement between T6 and T12 (p = 0.004). Interaction effects between time and inpatient treatment were significant only for percentage median BMI (p = 0.006) and interoceptive awareness (p = 0.008). Treatment satisfaction was high.\n\n\nConclusions\nMFT‐AN is an effective treatment for adolescents with anorexia nervosa. Continued improvement supports the added value of a 1‐year duration. MFT‐AN can be implemented both as a stand‐alone and adjunctive intervention.\n\n"]