Since the 1980s, there has been a steady rise in the performance and practice of religion within online environments. Starting with the formation of religious sub-groups on Usenet and email-based religious communities, a diversity of forms of religious engagement began to emerge and catch the attention of the media and academic world. Some examples include the creation of virtual temples or churches and sites of online spiritual pilgrimage (for a detailed review see Campbell, 2006). By the mid-1990s, scholars began to take serious notice and explore the development of these unique social-spiritual practices related to the Internet, and to speculate on the potential impact of importing offline religious beliefs and practices online. In the past decade, we have seen even more innovative and novel examples of religion spring up online from "godcasting" (religious podcasting) to religious versions of popular mainstream websites, such as Godtube.com to online worship spaces in Second Life for Christians, Muslims, and Jews. This chapter provides a critical review of the study of religion online, emphasizing how research on religion and the Internet has become an interdisciplinary area of study. It synthesizes previous research on religion and the Internet, and highlights one particular area at the focus of my own work: online religious communities. By focusing on how the study of religious community online has developed since the 1990s, this chapter demonstrates a progressive refinement of research themes, methods, and questions related to religion online. Furthermore, the chapter suggests how future studies of religion online may need to develop.The development of this research area can be seen in terms of maturing research questions and methods that can be framed in terms of three phases or "waves" of research. This provides a framework for understanding how religious community has been studied online in the past decade, advancing along with the further discoveries and developments in the field of Internet research. In each wave of research, the common themes and implications of these findings related to the study of religious community online are highlighted. Finally, this chapter addresses areas that have been neglected in research, and suggestsThe Handbook of Internet Studies Edited by Mia Consalvo and Charles Ess