Introduction: Although several studies have hexplored the development and dynamics of mental toughness, there is a notable scarcity of research addressing these aspects from a resource-based perspective. Objective: The study aimed to investigate the role of personal psychological resources in the relationship of social and organizational resources on mental toughness in secondary school varsity athletes. Through the lens of the Conservation of Resources (COR) theory, this study investigates the impact of external resources such as support from family, friends, coaches, and organizations on internal psychological attributes like hope, efficacy, resilience, and optimism, which together contribute to the development of mental toughness. Methodology: A total of 644 secondary school varsity players from Northern Mindanao, Philippines, were involved in the study. Results: The results showed that personal psychological resources served as a mediator in the relationship of social and organizational resources on the mental toughness of student-athletes. Specifically, athletes who reported receiving more resources from their social network and organizations exhibited increased personal psychological resources (i.e., hope, efficacy, resiliency, optimism) of which contributed to enhanced mental toughness. Conclusions: This study emphasizes the significance of a supportive environment in cultivating athletes' mental toughness and provides practical implications for sports organizations, educators, and coaches in creating interventions that improve personal psychological resources, and ultimately, mental toughness.