The relationship between personality dimensions and alexithymia was investigated in a sample of students. A correlational analysis was performed to assess the kind of associations among five personality dimensions (including neuroticism, extraversion, openness, agreeableness, and conscientiousness) with alexithymia and its three components difficulty (identifying feelings, difficulty describing feelings, and externally oriented thinking). Three hundred and forty six students (156 boys, 190 girls) from the University of Tehran were included in this study. All participants were asked to complete the Revised NEO Personality Inventory (NEO-PI-R) and the Farsi version of the Toronto Alexithymia Scale (FTAS-20). Analysis of the data involved both descriptive and inferential statistics including means, standard deviations, multivariate analysis of variance, Pearson’s Correlation Coefficients and regression analysis. Alexithymia showed a significant positive association with neuroticism as well as a significant negative association with extraversion and openness. The results also revealed that neuroticism, extraversion, and openness can predict changes of alexithymia and its three components. It can be concluded that personality characteristics will influence cognitive processing of emotional intelligence and regulation of emotions. Results and implications are discussed.