Although estimates of homelessness among Veterans have been declining since 2009 (the first year these data were reported), homelessness remains more common among Veterans compared to non-Veterans. Circumstances leading to homelessness are often complex because they can involve both community-level factors, such as local housing policies and market conditions, and factors at the individual level, such as having a mental health or substance use disorder. A social-ecological framework for understanding homelessness underscores that individual-level factors alone do not predict homelessness; rather, these factors characterize individuals who may be more vulnerable to broader societal and economic forces that create conditions of homelessness. Veterans may have unique individual-level vulnerabilities to homelessness, including those stemming from a history of combat exposure or experiences of military sexual trauma. They may also have unique protective factors, such as access to health care (including mental health care) and case management supports. The aim of this systematic review was to synthesize available evidence on factors associated with homelessness among Veterans to inform cross-VA efforts to reduce and prevent Veteran homelessness and identify research gaps. Ending Veteran homelessness is a VHA priority.