Purpose: To evaluate the effectiveness of an adaptation of Interpersonal Group Psychotherapy (IPT-G), in facilitating short- and longer-term improvements in eating disorder symptomology, psychosocial impairment, anxiety, depression and attachment difficulties among adults living with overweight and diagnosed with binge eating disorder (BED). Design/methodology/approach: In total, 24 participants completed measures at the start of IPT-G, mid-treatment, discharge and six-month follow-up. Quantitative outcomes were analysed utilising one-way repeated measures analysis of variance. Findings: Treatment retention was 100%. Significant improvements in binge-eating frequency, psychosocial impairment and depression were achieved at mid-treatment and maintained at post-treatment and six-month follow-up, and with large effect sizes. Attachment anxiety had reduced significantly at post-treatment and was maintained at six-month review. Body mass index (BMI) had stabilised by mid-treatment and was maintained at post-treatment and six-month follow-up. All hypotheses were supported, with the exception that attachment avoidance did not improve significantly and following a post-treatment reduction, anxiety symptoms deteriorated slightly by six-month follow-up, such that they were no longer significantly different from pre-treatment levels. Practical implications: Despite being the most prevalent of the eating disorders (compared to anorexia nervosa and bulimia nervosa), BED is under-recognised and under-treated in clinical settings. Results indicate the sustained effectiveness of IPT-G in improving eating disorder and comorbid symptomology associated with BED. Originality/value: This is the first UK study to investigate the effectiveness of IPT-G at treating BED. Unlike previous studies in the field, this study did not exclude participants based on age, BMI or psychiatric comorbidity.