Objective: Youth with posttraumatic stress disorder (PTSD) symptoms have significant difficulties regulating affective experiences; as a result, many engage in nonadaptive coping behaviors including deliberate self-harm (DSH). To identify youth with PTSD symptoms who may be most at risk for DSH, this study examined anxiety sensitivity (AS) as a moderator of the relationship between PTSD symptoms and DSH in a diverse sample of psychiatric inpatient youth with a history of potentially traumatic events (PTE). Method: Participants (N = 50; 52.0% female; Mage = 15.1 years, SD = .51; 44% White) completed a test battery that included measures of DSH frequency, depression, AS and PTSD symptomatology. Results: The proposed model accounted for 53.6% of variance in DSH, with PTSD symptoms being a significant predictor (sr2 = .11). The interaction of PTSD symptoms and AS accounted for an additional 4.5% of variance above and beyond covariates and main effects. Simple slopes revealed that the association between PTSD symptoms and DSH was significant for individuals scoring high (b = .25, SE = .06; t(50) = 3.83, p < .01) but not low (b = .03, SE = .10; t(50) = 0.30, p = .765) on the AS. Conclusions: Findings are consistent with theoretical and empirical work suggesting that DSH may be used to reduce emotional distress in the presence of maladaptive cognitive and emotional processes.