People generally participate in research for three primary reasons: financial, altruistic/social, and personal/psychological. While we would expect individuals with serious mental illness (SMI) to share these reasons, this assumption has not been investigated. Ninety-two adults with SMI living in supportive housing were interviewed about their reasons for participating in a study examining their housing, well-being, and community experiences. Associations between participant characteristics and reasons for research participation were explored. Primary reasons for participation included “contributing to science/research” (37%, n = 34), “money” (33%, n = 30), “improving housing” (22%, n = 20), “having someone to talk to (2%, n = 2) and other (6%, n = 6). Secondary reasons were “money” (38%, n = 31), “contributing to science/research” (24%, n = 20), “improving housing” (24%, n = 20), “having someone to talk to” (2%, n = 2) and other (11%, n = 9). Additionally, 29% (n = 27) reported making housing or well-being changes since participating. Individual characteristics were not significantly associated with reasons for research participation. Participants’ reasons for research participation mirrored the general population, with “improving housing” being a unique motivating factor. Participation in survey research could benefit people with SMI by prompting community engagement and consideration of housing issues.