Concerned partners (CPs) of service members and veterans who misuse alcohol face help‐seeking barriers and mental health problems. We used multiple regression to evaluate the efficacy of Partners Connect, a four‐session web‐based intervention (WBI) to address military CPs’ mental health and communication. We randomized 312 CPs to the WBI or a control group. Five months later, WBI CPs reported significant reductions in their anxiety and increases in their social support compared to control CPs. Intervention dose was also associated with improved WBI CP outcomes. Partners Connect appears to fill a need for families who face help‐seeking barriers and provides an alternative to traditional care for those who may not otherwise seek help.