The Department of Veterans Affairs (VA) is committed to preventing and ending homelessness among U.S. veterans, but there have been few estimates of the incidence of veteran homelessness and prospective studies to identify predictors of homelessness. This study examines the 1-year incidence of homelessness among veterans seen in VA specialty mental health clinics and identified sociodemographic and clinical predictors of homelessness. Using a retrospective cohort study design, data were extracted from the VA medical records of 306,351 veterans referred to anxiety and posttraumatic stress disorder clinics across 130 VA facilities from 2008-2012 and followed for 1 year after referral. Homeless incidence was defined as new use of any VA homeless services or a documented International Classification of Diseases (9th rev.) V60.0 (lack of housing) code during the year. Of the total sample, 5.6% (7.8% for women and 5.4% for men) experienced homelessness within 1 year after referral to VA specialty mental health care. Veterans who were unmarried or diagnosed with a drug use disorder were more than twice as likely to become homeless; those who were Black or had annual incomes less than $25,000 were more than one and a half times as likely to become homeless. Together, these findings suggest a notable and important percentage of veterans seen in VA specialty mental health clinics newly experience homelessness annually. Monitoring early signs of housing vulnerability and preventing homelessness in this vulnerable but treatment-engaged population may be important in the VA's efforts to end veteran homelessness.