Background: Active Support (AS) is an approach for promoting increased engagement in activities by people with intellectual disability (ID). Method: We critically reviewed the available research on AS, and added a commentary to help guide future research and practice. Results: Despite weaknesses in the research design of some studies, there is consistent evidence that AS results in increased engagement in activities. There is also some limited evidence of other beneficial outcomes. All published research to date has involved people with ID in community group homes with 24-hour staffing. Conclusion: The established efficacy of AS for increasing engagement means that research attention can now be given to: (a) developing AS to enhance its positive impact on outcomes such as choice and relationships; (b) exploring the wider implementation of AS beyond community group homes and people with ID; and (c) examining the effectiveness of wide-scale implementation of AS, with careful attention to issues such as management, organisational and staffing factors, and cost. (Contains 4 tables and 1 note.)