The question of agency has been neglected in social network research, in part because the structural approach to social relations removes consideration of individual volition and action. However, recent emphasis on purposive individuals has reignited interest in agency across a range of social network research topics. Our paper provides a brief history of social network agency and an emergent framework based on a thorough review of research published since 2004. This organizing framework distinguishes between an ontology of dualism (actors and social relations as separate domains) and an ontology of duality (actors and social relations as mutually constituted) at both the individual and the social network level. The resulting four perspectives on network agency comprise individual advantage, embeddedness, micro-foundations, and struc-turation. In conclusion, we address current debates and future directions relating to sources of action and the locus of identity.