--- - |2+ Background Although individuals with posttraumatic stress disorder (PTSD) report poor tolerance for distress, the mechanisms underpinning this are unknown. Cognitive models of PTSD propose that appraisals of lacking or losing control impair adaptation to trauma. This study investigated whether avoidance of emotional distress was affected by loss of control in a web‐based community sample with and without PTSD symptomatology, expecting that those with PTSD may show more detrimental effects following greater loss of control. Methods PTSD‐symptomatic (N = 104) and nonsymptomatic (N = 102) participants initially had baseline controllability appraisals indexed during a task designed to induce an illusion of control over an unwanted stimulus. Participants were then randomized to be able to delay the onset and also control the termination of interference trials during an effortful visual search task, and separately randomized to receive pretask instructions implying either doubtful or certain controllability. Following the manipulation, participants completed a task indexing delay between selecting and playing a purportedly distressing video at their maximum tolerable distress level. Results Controlling for age, sex, and instructional condition, those who experienced greater violation of their initial perceptions of control tended to be more avoidant of emotional distress. There was a significant interaction whereby loss of control was more detrimental for those with PTSD symptoms. Conclusions These initial data suggest that posttraumatic stress exacerbates sensitivity to loss of control, and this appears to directly impact capacity to approach distressing stimuli. - Depression and Anxiety, EarlyView.