Background: Academic stress is the most common emotional or mental state that students experience during their education. In this context, What role can personality dimensions and spiritual intelligence play in level of the students' academic stress? Aims: Given the importance of recognizing the determinant and influencing variables on students 'academic stress, the present study aimed to investigate the moderating role of spiritual intelligence in the relationship between hexaco personality dimensions and students' academic stress. Method: This research was an exploratory research of correlation type. The statistical population of this study consisted of all third year high school students of Ardebil city in the academic year 2018-2019. From this community, 240 people were selected through multistage cluster random sampling. Research tools included Academic Stress Inventory (Ang & Huan, 2006), Hexaco Personality Inventory (Lee & Ashton, 2004), and Spiritual Intelligence Scale (King, 2008). Data were analyzed using Pearson correlation test and adjusted multivariate regression analysis. Results: The results of adjusted regression analysis showed that spiritual intelligence had a moderating role on the relationship between all hexaco personality dimensions, except for honesty-humility and extraversion, with students' academic stress (p<0/001). In other words, with the increase in spiritual intelligence, the relationship between hexaco personality dimensions and students' academic stress becomes weaker. Conclusions: According to the results of this study, spiritual intelligence by moderating the relationship between hexaco personality dimensions and students' academic stress can reduce the occurrence of these types of stresses due to personality dimensions.