Participation is a central aspect of human functioning and a key focus of research and practice in the intellectual disability field. However, there is not an accepted definition of participation that guides research and practice. To inform the development of a definition, a scoping review of the intellectual disability literature from 2001-2015 was conducted. Findings suggest that existing research rarely uses definitions of participation, but does examine participation across multiple domains and addresses issues of access and inclusion. Less focus was placed on individual aspects of participation such as meaning, responsibility, and choice. Based on the findings, implications for future research and practice are provided.