Students.

This study aimed to examine the relationship between perceived family functioning, distress tolerance, and academic self-discipline, with the mediating role of mental vitality. The research method was correlational using structural equation modeling. The statistical population included all students at Imam Khomeini International University during the 2023-2024 academic year. A total of 260 students were selected as the study sample using cluster random sampling. Research instruments included the Family Functioning Questionnaire (Epstein et al., 1980), Academic Self-discipline Questionnaire (Afrooz, 2007), Distress Tolerance Scale (Simons & Gaher, 2005), and Mental Vitality Scale (Ryan & Frederick, 1997). Data were analyzed using structural equation modeling in AMOS 24 software. The findings indicated that the conceptual model had good fit indices. Examination of direct pathways showed that family functioning and distress tolerance were significantly related to academic self-discipline. Furthermore, analysis of indirect pathways revealed that mental vitality mediates the relationship between academic self-discipline and both family functioning and distress tolerance. The results suggest that students' academic self-discipline can be enhanced by improving their perceptions of family functioning, increasing their distress tolerance, and fostering their mental vitality.