Abstract: Aim: Moral injury (MI), originally studied in military contexts, refers to emotional distress resulting from actions that conflict with one's core values. MI outcomes may help explain how potentially morally injurious events (PMIEs) contribute to mental health issues, yet empirical evidence remains limited. This longitudinal study examined whether MI outcomes mediate the relationship between PMIE exposure during combat and posttraumatic stress symptom (PTSS) clusters following discharge.Method: We followed 374 male combat veterans over a five-year period. Pre-enlistment psychological characteristics were conducted 12 months prior to enlistment (T1). PMIE exposure was measured during the final month of military service (T2) using the Moral Injury Events Scale (MIES), capturing experiences throughout active duty. MI outcomes were assessed six months post-discharge (T3) using the Expressions of Moral Injury Scale-Military Version-Short Form (EMIS-M-SF). Finally, PTSS clusters were evaluated one year after discharge (T4) using the PTSD Checklist for DSM-5 (PCL-5).Results: A total of 48.7% of participants reported exposure to PMIEs, while 8% met criteria for probable PTSD. Path analysis demonstrated a direct effect of PMIE-betrayal (T2) on arousal and reactivity as well as negative alterations in cognition and mood symptom clusters (T4). Results also showed indirect associations between exposure to all PMIE dimensions (T2) and PTSS clusters (T4) via MI outcomes (T3).Conclusions: Findings underscore the role of MI outcomes in the development of specific PTSS clusters following PMIE exposure. Integrating MI-informed interventions may enhance treatment for veterans transitioning to civilian life. — A prospective 5-year study explored moral injury events, outcomes, and PTSD among 374 combat veterans.Combat service betrayal experiences directly predicted arousal and reactivity as well as mood-cognition symptom clusters.Moral injury outcomes mediated the link between potentially morally injurious events and PTSD symptom clusters.