Abstract Social inclusion of individuals with intellectual and developmental disabilities (IDD) is related to positive mental health and social outcomes; yet, individuals with IDD experience societal barriers that limit opportunities for community participation. Providing opportunities for interactions between individuals with and without IDD through peer mentoring may diminish barriers and improve community inclusion. Guided by the self-determination theory, the current report describes the development of a peer mentoring programme to promote the natural process of building intrinsic motivation and personal growth through opportunities for individuals without disabilities to socialize with individuals with IDD on a large university campus and throughout the surrounding community. The theoretical framework that informed the development of the peer mentoring programme is described, as well as the participants, the setting in which the programme is situated, the structure of the programme, the initial impacts and improvement of the programme over time, including approaches to sustainability, and implications for future research and practice.