Objective While major theories of non‐suicidal self‐injury (NSSI) emphasize the behavior's role in emotion regulation, little is known about the daily emotional experiences of self‐injurers. This study investigated the specific emotions that are characteristic of those who engage in NSSI. Method University students (n = 84) with either no history or a recent history of NSSI completed daily diary and retrospective measures of emotional experience. To evaluate generalizability of findings, the retrospective measure was also administered to a diverse sample of U.S. adults (n = 92) with and without histories of NSSI. Results Results indicate that self‐injurers experience greater negative emotionality, particularly self‐dissatisfaction, compared to individuals with no NSSI history. Self‐injurers also reported less positive emotion, but these effects were smaller. The pattern of results was similar when controlling for Axis I psychopathology and borderline personality disorder symptoms. Conclusions Individuals who engage in NSSI experience more negative emotions, generally, and more self‐dissatisfaction, specifically. Findings contribute to the growing literature on the role of emotion in the etiology and functions of NSSI.