PROJECT ABSTRACT Military spouses in relationships with a heavy drinking service member partner report high levels of depression symptoms, drinking, and social impairment, and a heightened risk for domestic violence compared to spouses who are not in a relationship with a heavy drinking partner, and these consequences are compounded when both partners drink heavily. Yet, spouses often do not seek care for their own or their partner’s problems due to multiple barriers preventing pursuit of care. Military spouses and partners —termed “concerned partners” (CPs)—may be an important gateway for motivating service members to seek care. However, CPs may first need to reduce their own drinking and improve their communication to effectively support and encourage changes for their service member partner. The proposed study builds off our pilot work with Partners Connect, a 4-session web-based intervention (WBI) for military CPs. In Aim 1, we propose a Sequential Multiple Assignment Randomized Trial (SMART) design to evaluate the efficacy of an adaptive CP intervention on CP drinking and SM help-seeking. In Aim 2, we will examine how and for whom the adaptive intervention is most efficacious by looking at moderators and mediators of service-member help-seeking and supplementing these quantitative analyses with qualitative CP and service member interviews on the reasons and drivers of service member help-seeking. We will conduct a two-stage SMART design. In stage one, we will randomize CPs to either Partners Connect or communication resources from the Gottman Institute website. CPs will be considered a ‘”responder” at stage one if their service member completes their personalized normative feedback (PNF) session. CPs who are non-responders to stage one (service member has not completed PNF) will be re-randomized to receive additional communication interventions in stage two. The purpose of the stage two randomization is to test what helps stage one non-responders. We expect that by further treating those that do not respond initially to Partners Connect, we can improve CP communication and drinking, and ultimately help service members access a brief, effective PNF intervention for their drinking. Our goal is to reduce health disparities in the military by first intervening with the service member’s spouse and improving their outcomes to better equip them to engage their service member in services. In doing so, we develop a model that increases treatment accessibility and appeal among a group that may not otherwise seek care. The optimal package for CPs is the one that improves the CP’s drinking, mental health, and communication and that ultimately engages the service member in PNF. Thus, Partners Connect is a novel “two-in-one” intervention that fills service gaps for CPs and service members.