The eating disorder clinical and scientific community advocates for the use of a shared approach to healthcare that actively involves patients and carers. A systematic review of the literature on guided self-help or self-help in anorexia nervosa (targeting either the individual affected by the illness or their carers) and meta-analyses of studies using randomised controlled designs for the evaluation of the outcomes: (1) drop-out from end-of-treatment assessment, (2) body mass index (BMI), (3) anxiety, (4) depression and (5) quality of life, were undertaken. Guided self-help was directed to patients in 15 studies and to carers in seven studies. The interventions were based on a variety of theoretical models, used different formats (books and digital materials), and were delivered by individuals with a range of experiences and expertise (e.g. individuals with lived experience of the illness, graduate students, or clinically trained professionals). Guided self-help was associated with significantly lower drop-out from the completion of end-of-treatment assessments compared to a control condition. There was an improvement in carers' wellbeing from skill-sharing interventions. Guided self-help may facilitate patients' treatment engagement and also improve carers' wellbeing.