In the present study, the mediating role of personality traits in the correlation between the level of adjustment to university life and well-being of university students, was examined. The sample group of the research is comprised of 437 university students in total (307 females, 70.3%, and 130 males, 29.7%). The sample size of the research was based on a confidence interval of 95% and data were obtained from participants using appropriate sampling methods. The Adjustment to University Life Scale, the Five-Factor Personality Inventory, PERMA scale and a personal information form were used as data collection tools. The contemporary approach suggested by Hayes (2018) was used in order to obtain valid and reliable results in the analysis of mediation models. The findings of the research suggest that there was a positive and significant correlation between personal, academic and social adjustment, well-being and personality traits such as extroversion, agreeableness, self-discipline and openness to experience, while there was a negative and significant correlation between the aforementioned and neuroticism. Moreover, it was concluded that personality traits such as extraversion, agreeableness, self-discipline, neuroticism, and openness to experience had a mediating role in the academic, social adjustment and well-being and that the indirect impacts of these personality traits were significant in this correlation. Based on these findings, it could be said that adjustment to university life is an important causal variable in well-being and that personality traits are also an important mediating variable in this correlation by playing a supportive and therefore protective role on students' well-being in terms of reducing the impact of problems they will face during the adjustment process to university life.