Personality affects how emerging adults select friends and how they are selected on social networking sites (SNSs). Big Five personality traits and frequency of contacts on SNSs were collected from 160 college freshmen (M =18 years) under a round-robin design over 2 months. Using social network analyses, we examined how personality and dyadic similarity affect online friend selections among new acquaintances. Our results show that people with high extraversion, neuroticism, and agreeableness and low openness selected more friends, verifying both the social enhancement hypothesis and the social compensation hypothesis. People with low extraversion, conscientiousness, and neuroticism and high openness were selected as online friends more often. Only openness dissimilarity had a salutary effect. We discuss the role of personality in social networking friend selection.