Abstract Research concerning the function of online contexts in adolescents’ everyday lives adds important pieces to the understanding of their identity development. Specifically, online contexts are distinguished from other everyday contexts with regard to the conditions for identity explorations, self-presentations, and social interactions. Understanding the meaning of these aspects of online contexts for identity development is thus an important research area. This review of research of identity online shows that research has so far primarily focused on identity expressions and less on identity development. Conversely, developmental identity research rarely includes online contexts. Thus, there is a gap between research about identity development and research about identity online. This article, therefore, aims to review research on identity online from a developmental perspective and to suggest directions for future research. The reviewed literature was structured around aspects where online contexts have brought about substantially changed conditions for identity development: the opportunities for identity explorations, means for self presentations, and requisites for social interactions. The conclusions are that research on identity development may further the understanding of adolescents’ online activities and that research on identity development needs to include online contexts to see the whole story of identity development for adolescents today. Keywords Online contexts Identity development  Identity processes Identity integration