The 2023 Kahramanmaraş-Hatay earthquakes in Türkiye resulted in significant collective trauma for affected populations. This situation highlighted the importance of understanding psychological factors that promote resilience and mental well-being in disaster contexts. Positive childhood experiences (PCEs) are crucial in shaping lifelong mental health, yet their impact in non-Western and disrupted settings is not well-studied. This research examined how resilience and psychological flexibility mediate the relationship between PCEs and adult mental well-being among 952 adults in Türkiye after the earthquakes. Using structural equation modeling, the study confirmed that PCEs significantly influenced mental well-being through both resilience and psychological flexibility. The findings provide a framework for understanding how early developmental strengths can enhance mental health in adulthood, particularly in the aftermath of disasters. This research contributes to resilience theory by demonstrating how early assets can mitigate the effects of collective trauma and suggests the need for culturally sensitive interventions that strengthen relational resources and foster adaptive psychological skills to maintain mental well-being throughout life.