Tabriz University of Medical Sciences Depiction of Health 2008-9058 16 4 2025 11 20 The Mediating Role of Self-Esteem in the Relationship between Thinking Styles and Types of Assertiveness in University Students 434 449 10.34172/doh.2025.34 EN Fariba Shahrokhi https://orcid.org/0009-0001-9666-0147 Mojtaba Tamadoni https://orcid.org/0000-0003-2320-8886 Journal Article 10.34172/doh.2025.34 2025 07 31 2025 12 10 Background. Thinking styles, self-esteem, and assertiveness are essential psychological concepts that influence how individuals interact with others and express themselves effectively. Although these three variables are important and have been studied before, the mediating role of self-esteem in the relationship between thinking styles and the two types of assertiveness (adaptive and aggressive) among students has been less explored. The present study aimed to examine the mediating role of self-esteem in the relationship between thinking styles and two types of assertiveness among university students. Methods. The statistical population of the current descriptive study consisted of students from several branches of Islamic Azad University in Tehran in 2024, with 306 participants recruited through convenience sampling. Data were collected using the Adaptive and Aggressive Assertiveness Scale, the Thinking Styles Inventory, and the Rosenberg Self-Esteem Scale. To test the hypothesis of self-esteem’s mediating role between thinking styles and assertiveness types, a path analysis based on structural equation modeling was conducted using SPSS and AMOS. Results. Findings indicate that the first and second thinking styles had significant positive relationships with self-esteem, whereas the third had a negative, non-significant relationship. The first thinking style had a positive impact, while the second and third styles showed adverse effects on both adaptive and aggressive assertiveness. Self-esteem, as a mediating variable, is crucial in these relationships. The research model explained 15% of the variance in self-esteem, 17% in aggressive assertiveness, and 27% in adaptive assertiveness, demonstrating a good model fit. Conclusion. These findings indicate that the connections between thinking styles and both types of assertiveness are intricate rather than simple or one-dimensional. Self-esteem may play a key mediating role in these relationships. Therefore, focusing on teaching effective thinking styles and enhancing self-esteem can improve adaptive assertiveness and reduce aggressive behaviors among students.