Experiences of belonging are a basic human need (Baumeister & Leary, 1995), and the accessibility of belonging might look different for individuals labeled with Intellectual and Developmental Disabilities (IDD) due to historic and ongoing exclusion. This qualitative, participatory study explored how adults with intellectual and developmental disabilities defined belonging, reflected on experiences of belonging, and co-constructed a conceptualization of belonging together. With a focus on presumptions of competence (Biklen & Burke, 2006), and epistemic agency (Taylor, 2018), this project includes individuals with lived experiences as opposed to proxy voices. Through a Disability Studies lens, the findings of this study (1) document co-researchers experiences of belonging, (2) describe belonging through five key components as illustrated in a co-constructed visual, and (3) document the alignment and power of participatory methods in centering the lived experiences of individuals with IDD in research. The project also suggests implications for schools, families, communities, and researchers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]