Background: Over 75% of Veterans referred for behavioral health assessments endorse significant relationship concerns. Relationship distress leads to a wide range of health and mental health problems, whereas healthy intimate relationships are an important part of biopsychosocial models of resilience and rehabilitation. Improving social functioning is an RR&D priority, and VHA directive 1163.04 mandates all Veterans have access to a flexible continuum of family mental health services. However, access to couples’ interventions is limited: trained couple therapists are limited in number and location, and they are underutilized due to logistical barriers couples face including coordinating schedules, dual time off work, childcare, and stigma. Because of these barriers, over 60% of divorced couples never accessed couples’ treatment, and Veterans spend four to seven years in relationship distress before getting help. Digital health is a critical part of solving problems of access to care. Digital interventions for couples provide flexible access to evidence-based relationship interventions and are essential for providing scalable access to family mental health care. OurRelationship is an online adaptation of an evidence-based couple therapy (Integrative Behavioral Couple Therapy), which combines eight hours of a self-paced online couples’ program with three 20-minute telehealth coaching sessions. Several RCTs show OurRelationship improves relationship functioning and individual mental health, including among community-recruited Veterans. Our pilot data from 13 couples recruited over two months in VA San Diego indicate Veterans find OurRelationship appealing and helpful. However, OurRelationship has not yet been rigorously evaluated with a Veteran population in a VA medical center setting. Methodology: The proposed 5-year study is a 2-month waitlist-controlled randomized clinical trial. We aim to serve 90 Veterans with mental health concerns and relationship distress and their partners (N = 180), recruited from individual and family mental health clinics within VASDHS. Data on rehabilitation outcomes including relationship functioning (primary outcome), relationship behaviors (e.g., communication, conflict), individual functioning (e.g., functional disability, family role), and psychiatric symptoms (e.g., depression, anxiety) will be collected at baseline, mid-program, post-program, and 6-month follow-up. We will collect participant feedback via qualitative interviews and quantitative ratings of therapeutic alliance and program satisfaction. Aims: Aim 1 is to examine feasibility and acceptability of implementing OurRelationship in a VA setting with Veterans and their partners. Aim 2 is to evaluate efficacy of the OurRelationship program on improving relationship functioning for Veterans and their partners. Aim 3 is to explore mediation of improvements in individual functional outcomes by improvements in relationship functioning. Career Development Plan...