This chapter offers both empirical and practical information concerning the online activity of individuals who engage in nonsuicidal self-injury (NSSI). To this end, the authors first provide an overview of the forms of online activity related to NSSI, and then focus on the motivations for – or function of – online NSSI communication. The authors also discuss the potential benefits and risks associated with online NSSI communication. Key implications for researchers in the field are outlined, as are research-informed recommendations to guide practitioners working with individuals who engage in NSSI and who may also participate in related online behavior.