© 2019, Springer Science+Business Media, LLC, part of Springer Nature.The present study aims to explore the nature of age and sex differences in personality constructs throughout the young adulthood; particularly differences on personality traits and interpersonal problems, on the basis of the five-factor model and the interpersonal circumplex model. The sample consisted of 514 participants from Turkey, 257 of whom were male, and 257 were female whose ages varied from 18 to 35 (M = 24.92). To strengthen the study results, participants in the sample were individually matched on both sex and age; so that there were same number of females and males at the same age. Results indicated that men were stronger in terms of openness and hostile-dominance, whereas women were stronger in neuroticism and agreeableness traits. Regarding age differences, conscientiousness had a significant increasing pattern whereas hostile-dominance had a significant decreasing pattern with aging throughout young adulthood. Implications of the findings were discussed in line with the literature considering stability versus change debate, and gender issues in personality within a cultural and developmental context.