Obese children have attended weight loss camps and residential programmes for more than 40 years. This paper provides the first systematic review of the effects of those programmes. Twenty-two studies met inclusion criteria (targeted and assessed change in weight status, minimal stay of 10 days and nights). Similar components across programmes included controlled diet, activities, nutrition education, and therapy and/or education regarding behaviour change. Participants lost substantial amounts of weight in all 22 studies, as measured by reductions in per cent-overweight during intervention. Eleven programmes included long-term follow-up evaluations. Compared with results highlighted in a recent meta-analysis of out-patient treatments, these immersion programmes produced an average of 191% greater reductions in per cent-overweight at post-treatment and 130% greater reduction at follow-up. Furthermore, mean attrition rates were much lower when compared with standard out-patient treatment. Inclusion of a cognitive–behavioural therapy (CBT) component seemed especially promising; follow-up evaluations showed decreased per cent-overweight at follow-up by an average of 30% for CBT immersion programmes vs. 9% for programmes without CBT. Explanations for the potentially greater impact of immersion relative to out-patient treatments are presented, including possibly differential effects on self-efficacy for both children and their parents.