Razi University

   Abstract Academic procrastination is one of the important issues in the field of learning and self-regulation, which can be associated with reduced academic performance, increased psychological distress, and difficulties in pursuing educational goals. Given the multidimensional nature of this phenomenon, simultaneous investigation of motivational, volitional, and emotional factors can contribute to a more comprehensive understanding of the mechanisms underlying academic procrastination. The present study aimed to explain academic procrastination among high school students based on Temporal Motivation Theory, with emphasis on the mediating roles of academic perseverance and perceived stress. The research method was descriptive-correlational and based on structural equation modeling. The statistical population included all male and female students enrolled in second-cycle high schools in Kermanshah during the 2025–2026 academic year, from whom 520 students were selected using convenience sampling. Data were collected using the Short Academic Procrastination Scale, Temporal Motivation Scale, Academic Grit Scale, and the Short Form of the Perceived Stress Scale. Data analysis was conducted using   -27 and SmartPLS-4, and direct and indirect relationships among variables were examined through structural equation modeling and bootstrapping procedures. Furthermore, the reliability and validity of the measurement model were assessed using Cronbach’s alpha, McDonald’s omega, composite reliability, average variance extracted, and discriminant validity indices. The findings indicated that the measurement and structural models demonstrated acceptable fit and quality, and the empirical data supported the proposed model structure. The results showed that success expectancy had a positive and significant effect on academic grit (?=0.225, t=2.724, P=0.007), and a negative and significant effect on academic procrastination (?=-0.256, t=3.075, P=0.002) and perceived stress (?=-0.264, t=2.837, P=0.005). Furthermore, impulsivity had a negative and significant effect on academic grit (?=-0.325, t=4.249, P<0.001) and a positive and significant effect on perceived stress (?=0.296, t=3.462, P=0.001). However, the direct effect of impulsivity on academic procrastination was not significant (?=0.069, t=0.896, P=0.371). Moreover, perceived stress had a positive and significant effect on academic procrastination (?=0.184, t=2.179, P=0.030). Task value positively and significantly predicted academic grit (?=0.259, t=3.705, P<0.001), whereas its direct effect on academic procrastination was negative but non-significant (?=-0.106, t=1.297, P=0.195). In addition, task value had a negative and significant effect on perceived stress (?=-0.343, t=4.149, P<0.001), and academic perseverance negatively and significantly predicted academic procrastination (?=-0.254, t=2.981, P=0.003).