Background: Social inclusion is central to disability policies internationally. The high risk of social exclusion for people with intellectual disability is compounded for those with challenging behaviour. Method: A systematic literature review examined how social inclusion of people with intellectual disability and challenging behaviour has been researched and operationalised in the empirical literature, and aimed to determine what evidence exists about the extent of social inclusion by people with intellectual disability and challenging behaviour. Results: A thematic analysis of the 14 papers identified that social inclusion has been poorly defined and measured, and that the little research that has occurred in respect of people with challenging behaviour has demonstrated their potential to be socially included. Conclusions: Clearer conceptualisation of inclusion, and greater understanding of practices that support social inclusion and system level mechanisms, which ensure goals around inclusion gain prominence in funding and support plans, may address the neglect of this critical quality-of-life domain for people with challenging behaviour. (Contains 1 table.)