Introduction Moral injury concerns transgressive harms and the outcomes that such experiences may cause. A gap in the literature surrounding moral injury, and an outcome that may be important to include in the mounting evidence toward the need for the formal clinical acknowledgement of moral injury, has to do with the relationship between moral injury and quality of life. No studies have examined this relationship in US military veterans—a population that is disproportionately exposed to potentially morally injurious events.

Methods A nationwide cross-sectional survey was conducted yielding 1495 military veterans. Participants were asked questions about moral injury and quality of life, among other things. Multivariable linear regression was used to characterise the adjusted relationship between moral injury and quality of life.

Results Moral injury (mean=40.1 out of 98) and quality-of-life (mean=69.5 out of 100) scores were calculated for the sample. Moral injury was inversely associated with quality of life in an adjusted model, indicating that worsening moral injury was associated with decreased quality of life (adjusted unstandardised beta coefficient (b)=−0.3, p<0.001). Results showed that age moderated said relationship, such that ageing veterans experienced an increasingly worse quality of life with increasingly severe moral injury (b=−0.1, p=0.003).

Conclusions Results of the study showed that moral injury was inversely associated with quality of life and that this relationship rapidly worsens with age. More work is needed to more precisely understand this relationship and to determine the best strategies for intervention.