Day programmes designed for young people with restrictive eating disorders offer intensive treatment options for individuals who have not made satisfactory progress through outpatient treatment but do not require hospitalisation. Existing literature consistently shows positive outcomes in terms of weight gain, reduced eating disorder and comorbid symptomology. However, it is crucial to note that although many day programmes consider family-based treatment a core framework, research on treatment outcomes for parents and the relationship between parent outcomes and adolescent outcomes remains limited. The current pilot study evaluated parent (n = 20) and adolescent (n = 13) outcomes of a new day programme for adolescents with restrictive eating disorders and their families. Results showed significant improvements across body mass index, eating disorder and comorbid symptomatology for adolescents and improvements in parent self-efficacy, parent mental health and a reduction in eating disorder accommodating behaviours. The findings suggest several potential mediators of day programme outcomes that could be tested in future research.