The assessment of impulsivity is complicated by the construct’s multi-faceted nature and poor correspondence between self-report and behavioral measures. These complications extend to populations anecdotally described as impulsive, including individuals who engage in nonsuicidal self-injury (NSSI). Research suggests that self-injurers report impulsivity, primarily negative urgency. Thus, negative affect may be an important prerequisite for increased impulsive behaviors. The present laboratory study examined self-report impulsivity differences between individuals with and without a history of NSSI and if self-injurers demonstrated behavioral impulsivity when experiencing negative affect. Undergraduates with (N = 54) and without (N = 61) a history of NSSI participated in a two-part laboratory-based study that investigated the role of affect manipulation in impulsivity and NSSI. Participants were randomly assigned to either a negative or a neutral-relaxing mood induction. Participants completed self-report measures of impulsivity, NSSI, and negative affect. A behavioral measure of impulsivity was administered during Session 1 (prior to a mood induction task) and again during Session 2 (following a mood induction task) to determine whether affect had an effect on behavioral impulsivity task performance. Self-injurers reported higher negative urgency and lack of perseverance but did not display impulsivity on the behavioral task, even under conditions of negative affect.