Childhood maltreatment increases the risk for posttraumatic stress disorder (PTSD) and comorbid substance use disorder (SUD). One pathway by which this occurs is through impaired emotion regulation. Past research has shown that negative urgency, a deficit in the regulation of negative emotions, is strongly related to PTSD in those with comorbid SUD. However, there is minimal research on the ... [Show full abstract] relation between positive urgency and PTSD in those with comorbid SUD. The current study investigated the association between childhood maltreatment, positive urgency, negative urgency, and PTSD symptoms among those with SUD. Results suggested that PTSD was associated with negative urgency and positive urgency overall. Childhood maltreatment did not moderate the association between negative urgency and PTSD. Childhood emotional abuse, emotional neglect, and sexual abuse moderated the relation between positive urgency and PTSD (ΔR(2) = .04 to .10). The association between PTSD and positive urgency was only significant at lower levels of emotional abuse and neglect. Future research should further examine the processing of positive emotions in those with PTSD and comorbid SUD. Findings might inform clinical interventions among populations exposed to childhood maltreatment to reduce or prevent the development of psychopathology.