BackgroundPerfectionism is significantly associated with symptoms of eating disorders in adolescents. Studies to date have not examined parent-supported CBT for perfectionism in eating disorders (CBT-P-ED). We co-designed the treatment and conducted a feasibility trial.MethodsEight parents of adolescents with eating disorders (M age = 48.75 years, 100% female) engaged in three co-design workshops to create a parent-supported CBT-P-ED self-help intervention. A further 10 parents (M age 41.8 years, 50% female) and their adolescent offspring (n = 10, M age 15.4 years, 60% female, 50% with self-reported diagnosis of anorexia nervosa) participated in a feasibility trial and provided feedback on the intervention.ResultsThe parents who engaged in the co-design workshops suggested several areas to optimise the perfectionism intervention, including using plain language, the impact of parental perfectionism, how to engage with their adolescent in treatment and the importance of increasing eating disorder specific material. Feedback from the feasibility trial suggested that the intervention was acceptable and feasible with 100% of parents and adolescents saying it was useful, and no attrition.ConclusionsParent-supported CBT-P-ED appears to be feasible. Future research is now required in a randomised controlled trial.