The interplay of personality and social relationships is as fascinating as it is complex and it pertains to a wide array of largely separate research domains. Here, we present an integrative and unified framework for analysing the complex dynamics of personality and social relationships (PERSOC). Basic principles and general processes on the individual and dyadic level are outlined to show how personality and social relationships influence each other and develop over time. PERSOC stresses the importance of social behaviours and interpersonal perceptions as mediating processes organized in social interaction units. The framework can be applied to diverse social relationships such as first encounters, short-term acquaintances, friendships, relationships between working group members, educational or therapeutic settings, romantic relationships and family relationships. It has important consequences for how we conceptualize, understand, and investigate personality and social relationships. Copyright © 2011 John Wiley & Sons, Ltd.