Exposure is an effective treatment for anxiety but many patients do not respond fully. Affect labeling (labeling emotional experience) attenuates emotional responding. The current project examined whether affect labeling enhances exposure effectiveness in participants with public speaking anxiety. Participants were randomized to exposure with or without affect labeling. Physiological arousal and self-reported fear were assessed before and after exposure and compared between groups. Consistent with hypotheses, participants assigned to Affect Labeling, especially those who used more labels during exposure, showed greater reduction in physiological activation than Control participants. No effect was found for self-report measures. Also, greater emotion regulation deficits at baseline predicted more benefit in physiological arousal from exposure combined with affect labeling than exposure alone. The current research provides evidence that behavioral strategies that target prefrontal-amygdala circuitry can improve treatment effectiveness for anxiety and these effects are particularly pronounced for patients with the greatest deficits in emotion regulation.