This guide is designed to be a simple introduction to the challenge of doing a grounded theory with online sources. A significant number of social settings are now online, and it is important to have effective ways of studying those settings. The guide gives a brief primer into the four key issues of grounded theory as a methodology for online studies. First, the guide discusses the background of grounded theory as a method. Second, the design of an online grounded theory study and the challenges that online sources bring to that design are discussed. Third, the range of online sources that can be used in an online grounded theory study is examined. Finally, a brief but practical illustration of how an online source might be coded, and some options for theoretical sampling are provided. The guide concludes by discussing some distinct advantages that the grounded theory approach might provide for online studies.