Abstract Combat theatres place service members in situations where they make difficult decisions that may transgress deeply held moral beliefs or witness others? acts of betrayal. Although many veterans are resilient to these types of experiences, for others, failure to accommodate these events may result in internal conflict that is theorized to lead to the development of moral injury. Moral injury is distinct from posttraumatic stress disorder (PTSD) and has been associated with poor mental health outcomes (e.g., depression, anxiety, suicidality) and alcohol/drug use among veterans. Few evidence-based interventions have been developed to target symptoms of moral injury. In studies with combat wounded veterans, community veterans, and a predominantly VA treatment- seeking sample, our team has demonstrated that mindfulness moderates associations between moral injury symptoms and negative mental health outcomes. In addition, we have demonstrated that combat wounded veterans are willing to take part in a mindfulness-based moral injury intervention, especially if administered in an online interactive web-based program. Using an iterative developmental process, the goal of this project is to adapt an integrative and theory-driven mindfulness-based intervention delivered online to target moral injury in combat wounded veterans. Aim 1 is to modify an evidence-based, online, interactive, instructor-delivered, six- session mindfulness program, originally designed to help active duty members manage physical pain (i.e., Mindfulness to Manage Chronic Pain [MMCP]), such that it addresses the psychologically painful symptoms (e.g., guilt, shame) characteristic of those with moral injury. The newly adapted program, Mindfulness to Manage Moral Injury (MMMI), will then be piloted with one group of eligible combat wounded veterans (N = 6) to generate qualitative feedback on program content and format; revisions based on this feedback will result in preliminary manualization. Subsequently, in Aim 2 we propose to develop a facilitator-led online interactive Education Support (ES) program designed to serve as a control comparison intervention, and then carry out a non- randomized pilot study comparing the feasibility (i.e., credibility, acceptability, study completion, and adherence (e.g., to homework assignments) of ES to the revised MMMI program with N = 20 (10 MMMI; 10 ES) combat wounded veterans. Following this phase of feasibility testing, we will also collect qualitative information and further refine both the MMMI and ES materials. In Aim 3, we propose a small-scale randomized controlled trial (N = 60 combat wounded veterans; 30 MMMI; 30 ES) to collect data on recruitment, credibility and acceptability, completion rates, and adherence in the two newly refined intervention arms at pre-post-test. Aim 3 will assess for potential primary and secondary outcome measures and lay the groundwork for a large-scale randomized R01 controlled efficacy trial. If supported, this work would have the potential to provide a novel and flexible theoretically grounded form of treatment delivered in-home for combat wounded veterans experiencing moral injury symptoms and associated mental health problems.