Purpose: In this study, the aim was to investigate pre-service teachers' cognitive flexibility in terms of specific variables and determine the relationship between pre-service teachers' cognitive flexibility and interpersonal problem solving skills. Research Methods: The study was designed in descriptive correlation model. Data were collected via the Cognitive Flexibility Inventory and Interpersonal Problem Solving Inventory from 531 pre-service teachers who studied in the Primary Teacher Training Departments during the fall semester of the 2017-2018 academic years. Findings: The findings indicated that there were significant differences according to gender and maternal education status, while there were no significant differences according to class level, department, and fathers' education status, socioeconomic and socio-cultural status. In addition, there was a relationship between pre-service teachers' cognitive flexibility and interpersonal problem solving skills.