This pilot randomized clinical trial tested an emotion regulation enhancement to cognitive behavior therapy (CBT) with 29 college student problem drinkers with histories of complex trauma and current clinically significant traumatic stress symptoms. Participants received eight face-to-face sessions of manualized Internet-supported CBT for problem drinking with or without trauma-focused emotion regulation skills (Trauma Affect Regulation: Guide for Education and Therapy [TARGET]). Both interventions were associated with sustained (at one-month follow-up) reductions in self-reported drinking frequency, drinking-related impairment, and heavy drinking in the past week, as well as Post-Traumatic Stress Disorder (PTSD) and complex PTSD symptoms, and improvement in self-reported emotion regulation. The enhanced intervention was associated with significantly greater sustained reductions in complex PTSD symptoms and resulted in medium/large effect size reductions in days of alcohol use (versus small effects by CBT). Emotion regulation enhancement of CBT for college student problem drinkers with interpersonal trauma histories warrants further investigation.