There is a significant need for 'wraparound' treatment services in VA housing for addressing SUDs. Homeless Veterans with SUDs are vulnerable to treatment dropout, rendering them susceptible to relapse, while their continuation in outpatient care during their participation in VA housing leads to improved clinical outcomes. According to systematic reviews, individual motivational interviewing reduces the incidence of substance use disorders, when compared to no treatment, but is labor intensive. As VA moves toward a 'Housing First' paradigm where greater numbers of homeless Veterans will continue to use substances while in VA housing, delivery of GMI (which may be less labor intensive) to these patients will be important for initiating and maintaining their recovery as well as enhancing their psychosocial integration and quality of life. In a prior controlled trial conducted by the Principal Investigator, GMI resulted in significantly higher outpatient treatment engagement and lower substance use compared to treatment-as-usual among dually diagnosed Veterans.