Background: Previous research has found that active support is effective at increasing levels of participation in activities and supporting a good quality of life for people with intellectual disabilities. However, there has been little research on the effect of active support on other outcome measures. Methods: This study uses observational methodology, combined with staff-rated measures, to explore the impact of the implementation of person-centred active support on the lives of 30 people with severe and profound intellectual disabilities living in small group homes. Results: Analysis indicated that significant increases in both the amount of assistance people received and the quality of that assistance were accompanied by significant increases in engagement, participation, choice-making opportunities and a significant reduction in challenging behaviour and in particular, self-stimulatory behaviour. Conclusions: The paper discusses the implications of the findings for both practice and for further research.