The purpose of this study was to examine the relations between the five big personality traits (openness, conscientiousness, extraversion, agreeableness, neuroticism) and attitudes towards seeking professional psychological help in counseling students along with the mediating role of cognitive flexibility. The sample of the study consisted of 189 students (140 female and 49 male) attending the counseling program at Istanbul Medipol University. The age mean of the sample was 20.81 (SD=1.91). The data were collected in the fall term of the 2018 to 2019 academic year. The Big Five Inventory, Attitudes Toward Seeking Professional Psychological Help Scale and Cognitive Flexibility Scale were used as data collection instruments. The data were analyzed by using SPSS 20 Statistical Package Program and the mediation model was tested in SPSS using PROCESS macro developed by Hayes. Results revealed that cognitive flexibility has mediator role between big five traits and psychological help-seeking attitude. In conclusion, the proposed model has emerged statistically significant.