Purpose: In this study, the relationship between the cognitive flexibility score of university students and their social interest levels was investigated. In line with this main purpose; the moderator role of variables such as age, department and grade on this relationship was also examined. Design/Methodology/Approach: The participants of the study consist of, 344 female and 256 male totally 600 undergraduate students. The research was designed in correlational survey model. “Social Interest Scale” and “Cognitive Flexibility Inventory” were used to collect data. SPSS PROCESS was used in the analysis of the data. The linear regression statistical technique was used to determine the moderation effect. Findings: Positive and significant relationship at medium level was observed between cognitive flexibility and social interest levels of university students. Results; social interest, age, and department are significant predictors of cognitive flexibility. Highlights: It was observed that high social interest scores caused an increase in the cognitive flexibility scores of the participants in the group at the age of 24 years and older. While the moderation effect of social interest on cognitive flexibility is at the highest level in psychological counseling and guidance department considering undergraduate students, this group is followed by undergraduate students from primary school teaching and preschool teaching departments, respectively.