Background: A meta-analysis examined the effects of deinstitutionalisation on adaptive behaviour outcomes in persons with intellectual disability. The need for an updated review in this area is reflected by recent policy shifts in community care practices and the international status of deinstitutionalisation efforts. Method: Twenty-three studies were compared using standardised mean effect sizes across 5 demographic, 4 methodological, and 1 outcome variable. Results: Moderate habilitative gains were found in 75% of adaptive behaviour domains. A weighted linear multiple regression revealed that larger effect sizes were significantly predicted by sample size and research design. Disability level also moderated the extent to which sample size affected the magnitude of effect sizes. Conclusions: These results are discussed in relation to the implications they have for community services for persons with intellectual disability. The difficulties in accurately comparing studies with dissimilar procedures and contexts are also outlined. (Contains 4 tables and 1 figure.)