Among emerging adult populations, the increasingly prevalent use of online social media, such as Facebook, and its relationship to individual personality traits and interpersonal relationships are of growing interest to researchers. The current study sought to investigate how attachment style, personality traits based on the Five Factor Model, and self-esteem were related to perceptions of interpersonal competency and Facebook use. Using data collected from 463 emerging adults in college, we conducted three hierarchical multiple linear regression models which suggested that (a) extraversion was positively related to Facebook use, (b) attachment style, extraversion, agreeableness, and openness were positively related to two aspects of interpersonal competency, and (c) Facebook use was negatively related to competence with initiating interpersonal relationships. Future directions for research and practical implications are also discussed. (Contains 3 tables.)