Behavioural weight management interventions consistently produce 8–10% reductions in body weight, yet most participants regain weight after treatment ends. One strategy for extending the effects of behavioural interventions has been the provision of extended care. The current study is a systematic review and meta-analysis of the literature on the effect of extended care on maintenance of weight loss. Through database searches (using PubMED, PsychInfo and Cochrane Reviews) and manual searches through reference lists of related publications, 463 studies were identified. Of these, 11 were included in the meta-analysis and an additional two were retained for qualitative analysis. The average effect of extended care on weight loss maintenance was g = 0.385 (95% confidence interval: 0.281, 0.489; P < 0.0001). This effect would lead to the maintenance of an additional 3.2 kg weight loss over 17.6 months post-intervention in participants provided extended care compared with control. There was no significant heterogeneity between studies, Q = 5.63, P = 0.845, and there was minimal evidence for publication bias. These findings suggest that extended care is a viable and efficacious solution to addressing long-term maintenance of lost weight. Given the chronic disease nature of obesity, extended care may be necessary for long-term health benefits.