PurposeThis study examines the moderating effect of gratitude on the mediating effect of deliberate rumination on the relationship between intrusive rumination and post-traumatic growth (PTG).MethodsWe used self-report questionnaires to collect data from 450 18–68-year-old participants (Mage = 39.73, SD = 13.73) residing in major cities and regions across South Korea. Data that were collected from 411 participants were subjected to analysis. Version 25 of SPSS (Statistical Package for Social Science) and PROCESS macro were used to analyze mediation, moderation, and moderated mediation effects.ResultsDeliberate rumination mediated the relationship between intrusive rumination and PTG. Gratitude moderated the effect of deliberate rumination on PTG. Finally, gratitude moderated the mediating effect of deliberate rumination on the relationship between intrusive rumination and PTG.ConclusionDeliberate rumination and gratitude facilitate PTG for traumatized adults. In particular, gratitude reinforces the effect of deliberate rumination on PTG.