Despite the theoretical emphasis on the role of emotion dysregulation in deliberate self-harm (DSH), few studies have examined this relationship. The present study sought to examine the role of emotion dysregulation in DSH by extending the findings of Gratz (2006) regarding the environmental (i.e. childhood maltreatment) and individual (i.e. emotional inexpressivity and affect intensity/reactivity) factors associated with DSH among 249 female undergraduates. Specifically, the present study examined whether emotion dysregulation (a) is associated with DSH above and beyond these other risk factors and (b) mediates the relationship between these risk factors and DSH. Findings indicate that overall emotion dysregulation distinguished women with frequent DSH from those without a history of DSH, adding reliably to the prediction of DSH status above and beyond maltreatment, inexpressivity, and affect intensity/reactivity. Moreover, among self-harming women, emotion dysregulation accounted for a significant amount of additional variance in DSH frequency and mediated the relationship between emotional inexpressivity and DSH frequency. Results also suggest the particular relevance of two specific dimensions of emotion dysregulation to DSH: limited access to effective emotion regulation strategies and a lack of emotional clarity, each of which reliably improved the prediction of DSH status and accounted for unique variance in DSH frequency among self-harming women above and beyond the other risk factors in the models. Results suggest the potential utility of teaching self-harming women more adaptive ways of responding to their emotions, including nonavoidant strategies for modulating emotional arousal and the ability to identify, label, and differentiate among emotional states.