Research results have provided evidence of the potential contribution that professional learning communities (PLCs) can make to enhance school outcomes. While numerous organizational and cultural aspects of schools have been recognized as key requirements for PLC success, researchers have noted that a teacher's ability to share knowledge in the context of school learning interactions requires certain skills. Our goal is to extend the theoretical understanding and practical implications of individual factors that may support and/or constrain PLC development. Specifically, we discuss teachers' personality traits from the big five typology, namely, extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience, as a possible explanation for differences in motivation toward social interactions, knowledge sharing, and the general position of the individual teacher in the PLC network. We also address the principal's role in promoting the process of knowledge sharing and social relationships in PLCs. Practical implications for school members and principals are suggested.