This chapter focuses on the future directions for NSSI research, providing an overview of recent and exciting research in two critical areas: the specificity of NSSI and heterogeneity within NSSI. To better understand what differentiates NSSI from other disorders or behaviors, research on NSSI and emotion regulation, comorbidity, clinical severity, and interpersonal sensitivity are reviewed. To better understand the heterogeneity of NSSI, research is reviewed on the role of adverse life events in NSSI, racial and ethnic differences in NSSI, differences in suicide risk in NSSI, and predictors and trajectories of NSSI over time. Finally, this chapter highlights a variety of potential future directions in these and other areas of NSSI research.