Social capital is the idea that one's relationships and social networks serve as a form of capital, operating as reciprocal networks of material, financial, social, and emotional resources and support. Social capital can be a powerful concept to help increase people with intellectual and developmental disabilities' (IDD's) inclusion, social ties, wellbeing, and quality of life. Despite people with IDD being more socially isolated, less attention has been drawn to social capital in the IDD field. The aim of this study was to examine people with IDD's (n = 5,493) social capital-related outcomes--quality of life outcomes related to social capital (i.e., people have intimate relationships; people participate in the life of the community; people have friends; people are respected; people are connected to natural support networks; people live in integrated environments; people interact with other members of the community; and, people perform different social roles)--using secondary Personal Outcome Measures interview data. People with IDD had an average of 42.25% social capital-related outcomes present. Social capital-related outcomes differed based on age, primary communication method, decision-making authority, race, support needs, residence, housemates, and employment/day settings. Social capital-related outcomes increased people's quality of life. Facilitating the social capital of people with IDD with meaningful reciprocal relationships and integration is a must.