Objective: This study examined the relationships among deliberate rumination, post-traumatic growth (PTG), self-transcendence, and gerotranscendence in older adults who have experienced loss. Specifically, the study investigated whether deliberate rumination influences PTG, and self-transcendence mediates the relationship between PTG and gerotranscendence. Methods: A structural equation model was established with data from 265 adults aged 65 years and older, who had experienced losses related to health, relationships, or bereavement. Analyses were performed using SPSS 29.0 and AMOS 29.0. Results: Significant positive correlations were observed among deliberate rumination, PTG, and self-transcendence. In addition, gerotranscendence was significantly and positively correlated with both PTG and self-transcendence. Structural equation modeling indicated that the research model had a better fit than the alternative model, demonstrating that deliberate rumination influences posttraumatic growth, and that posttraumatic growth affects gerotranscendence through the mediation of self-transcendence. In the research model, individuals who engaged in higher levels of deliberate rumination experienced greater PTG, which enhanced self-transcendence, ultimately promoting gerotranscendence. Notably, the direct effect of PTG on gerotranscendence was not significant, indicating that self-transcendence fully mediated this relationship. Conclusions: This study contributes to the understanding of psychsocial development in older adults and provides foundational data for future research by identifying the paths among deliberate rumination, PTG, self-transcendence, and gerotranscendence in the context of loss.