The associations between social support and stress with internalizing symptoms (depressive symptoms and hopelessness) and hazardous drinking were tested in an inpatient sample of suicidal military personnel. Baseline data from a randomized clinical trial were analyzed. Different sources of support and stressors in the social context of military personnel were differentially linked to internalizing symptoms and hazardous drinking. In the full sample (n = 192), family and nonfamily support were both inversely associated with internalizing symptoms but not hazardous drinking. Family stress was positively associated with internalizing symptoms. In a subsample of service members who had a history of deployment (n = 98), postdeployment social support was protective against internalizing symptoms, whereas deployment harassment was associated with increased odds of hazardous drinking. Results underscore the need for assessment of various dimensions of social support and stress to guide case formulation and optimize strategies to support patients’ mental well-being and adaptive coping.