Identity and online social networks are phenomena of our time and the search for and research on it is as powerful as the technological change in the history of the globalised world. On the one hand online social networks offer individuals the opportunity to create multiple identities based on valid information, and on the other hand acknowledge the fact these identities might be false and based on misinformation. In spite of the increased use of online social networks, limited research, especially from a communicative perspective, has been conducted on social processes and phenomena which are used to create online identities. One reason might be the social implications from the formation and use of online identities and advancement in processes of their transference into the real world. Based on recommendations by Acun (2011) and Attrill & Jalil (2011) that future research should focus on a theoretical exploration of identities in online social networks, this study sets out to investigate and address these gaps and to present a theoretical overview of the social processes and phenomena in the formation of identity in online social networks through an interpretivistic paradigm to gain an in-depth understanding of the phenomenon. Drawing from social constructionism, social categorization, identity, social identity and knowledge management theoretical paradigms, as well as a consideration of the notional constructs of identity and online social networks, the main theoretical approaches to and key criteria thereof are proposed. This article therefore aims to serve the purpose to review the theoretical perspectives used to explain the formation of identities in online social networks and to identify the characteristics and factors that impede on it