Posttraumatic stress disorder (PTSD) is characterized by strong negative emotions, often in response to trauma cues or reminders. Subsequent emotion regulation strategies impact the maintenance of PTSD symptoms and other trauma-related outcomes (depression, substance use). This study aimed to examine a range of trauma-cued emotions to enhance our understanding of changes following treatment and their potential role in improving relevant outcomes. Participants included 67 veterans diagnosed with PTSD and a substance use disorder who completed a dual diagnosis residential program that used cognitive processing therapy. At pre- and posttreatment, we measured 8 negative emotions following a trauma recall and PTSD symptoms, depressive symptoms, and negative urgency (impulsivity following negative emotions) as treatment outcomes. We used t-tests to assess changes at posttreatment and a within-subjects mediational analysis to test whether changes in trauma-cued emotions mediated treatment outcomes. Participants reported moderate, significant decreases for 5 emotions at posttreatment: anger at self, disgust at self, fear, guilt, and sadness (d ≥ 0.50), whereas nonsignificant changes were found for anger at others, disgust at others, and shame. Mediation analyses indicated greater reductions in trauma-cued sadness had a significant indirect effect on improvement in PTSD symptoms, depressive symptoms, and negative urgency. Reductions in disgust at self and fear also demonstrated a significant indirect effect on depressive symptom improvement. In this dual diagnosis program, veterans reported a significant reduction in some, but not all, trauma-cued emotions, and improvements in only select emotions accounted for a significant portion of improvement in relevant treatment outcomes.