The objective of this dissertation was to conduct an evaluation of a knowledge mobilization process in a community-based organization that supports adults with intellectual disabilities. The aim of the project was to understand how stakeholders share knowledge, use knowledge, and collaborate to make decisions regarding practices to support friendships for adults with intellectual disabilities. We produced two literature reviews; one systematically documented the views of adults with intellectual disabilities with regard to their relationships, and the other examined existing literature on strategies to support friendships. We also conducted two primary research studies in which we documented and evaluated knowledge mobilization activities in community-based organizations. We used a mixed-methods approach and collected data from a variety of stakeholder groups associated with a community-based organization, including staff members and the organization’s director, adults with intellectual disabilities, and family caregivers. Additionally, we collected data from staff working in a variety of community-based organizations that support adults with intellectual disabilities. During our primary research studies, we produced a variety of knowledge mobilization outputs regarding friendship support, including an evidence brief, a conference presentation, online presentations in French and English, and an informational website in French and English. The results of the studies included in this dissertation, our recommendations regarding community-based knowledge mobilization, and the knowledge mobilization outputs we developed can be used to improve knowledge mobilization practices in community-based services. Studying knowledge mobilization to support individuals with intellectual disabilities highlights some of the complexities that should be considered within community-based services, such as working with a variety of stakeholder groups, and including stakeholders that are potentially vulnerable to social exclusion.