Developmental support agencies support many adults with intellectual disabilities in the community. Unfortunately, these adults often exhibit high rates of challenging behaviour, which present significant pressures on these service providers. Agencies need to develop effective means of increasing their capacity to provide quality support. Previous systematic reviews found that training staff in positive behaviour supports can improve outcomes; however, the factors facilitating training's effects, long-term effectiveness, and outcomes for service users have yet to be determined. We conducted a scoping review of 98 journal articles and book chapters to develop a model for fostering capacity development drawing from Organizational Behaviour Management and Knowledge Translation theories. Some relevant factors include features of the inner and outer organizational contexts, training approaches (e.g., behavioural skills training & in-situ coaching), ongoing support and feedback. This model may lead to more effective and enduring treatment programs and improved support for adults with intellectual disabilities.