The purpose of this study was to examine the relationship between cognitive flexibility levels and personality traits of university students and whether these variables differ according to gender, education department, cigarette and alcohol use. The research was carried out with 151 students studying in the English language education, physical education and sports, science education, public relations and advertising departments of Karadeniz Technical University. "Cognitive Flexibility Scale" was used to measure the level of cognitive flexibility, "Eysenck Personality Questionnaire Short Form" to measure personality characteristics and "Personal Information Form" created by the researcher was used for personal information. Independent Sample T-Test, One Way Variance Analysis (ANOVA) and Pearson Correlation Coefficient were used in the analysis of the data. The analyses were carried out in SPSS 22.0 program. The results of the research showed that there was a negative relationship between cognitive flexibility and neuroticism and a positive relationship between cognitive flexibility and extraversion. According to another result only estraversion scores differ by gender. Women's extraversion scores were higher than men's scores. The variables don't differ according to the education department. Cognitive flexibility and psychoticism scores differ between smokers and non-smokers. In addition neuroticism and psychoticism scores differ between individuals who consume alcohol and do not consume alcohol. The findings were discussed based on the literature and suggestions for future research were presented. [Note: the citation on the PDF is incorrect.]