Homelessness is a major public health problem, and serious mental illness (SMI) is highly prevalent in the homeless population. Although supported housing services-which provide permanent housing in the community along with case management-improve housing outcomes, community integration typically remains poor, and little is known about the underlying determinants of poor community integration postresidential placement. The general SMI literature has indicated that motivational and cognitive ability factors are key determinants of successful community integration, which provides a foundation for examining this issue. This study evaluated whether interview- and performance-based assessments of motivation, nonsocial and social- cognitive ability, and psychiatric symptoms were associated with community integration indices in 2 samples of homeless veterans either with (N = 96) or without (N = 80) a psychotic disorder who had recently been admitted to a supported housing program but who had not yet attained housing. Motivation indices, including experiential negative symptoms and defeatist performance attitudes, stood out as the most robust correlates (rs=-.30 to -.69) of community integration across both samples, particularly for social role participation. Demographics, general psychiatric symptoms, and nonsocial cognition showed generally weak relations with community integration, though social cognition showed a few relations. The consistent findings across samples point to the importance of motivational factors for understanding the determinants of poor community integration in this complex population. Further, interventions that target motivational challenges may have widespread usefulness for enhancing community integration outcomes beyond obtaining housing.