Introduction: Mental health and positive cognitive attitudes are key factors in explaining students' academic success. Among them, students' psychological capital plays a pivotal role in creating motivation and expectations of success in them.Purpose: The present study aimed to test the mediation of subjective well-being and academic resilience in the relationship between academic optimism and academic vitality in first-year high school students.Methodology:The research method was descriptive-correlational and based on the structural equation model (SEM). The statistical population of the study was female students in the first year of high school in Tehran in the academic year 1403-1404. The research sample was 212 students who were selected using multi-stage cluster sampling method. To collect data, the students completed the Shannon-Moran, Bankole, Mitchell, and Moore (2013) academic optimism questionnaire, Dehghani Zadeh and Chari's academic vitality (2012), Tennant et al.'s Subjective Well-Being Questionnaire (2007), and Samuels' academic resilience (2004). The data were processed using the correlation matrix method and AMOS software to determine the fit of the causal model (path coefficient). Findings:: The results showed that the structural model using structural equation modeling is in the range of appropriate fit, which indicates the appropriate fit of the overall research model to the data. Academic optimism has a direct and significant effect on students' academic resilience (P≥0.01). Academic resilience has a direct and significant effect on students' academic vitality (P≥0.01). Academic optimism has a direct and significant effect on students' subjective well-being (P≥0.01). Subjective well-being has a direct and significant effect on students' academic vitality (P≥0.01). Academic optimism has a direct and significant effect on students' academic vitality (P≥0.01). Also, the total path coefficient between academic optimism and academic vitality was significant. Academic optimism, academic resilience, and well-being together explain 27 percent of the variance of the academic vitality variable. Result: By planning and implementing educational measures, holding educational classes in schools, the level of academic optimism, academic vitality, mental well-being, and academic resilience in students can be strengthened.