Objective Exposure and response prevention (ERP) is an effective treatment for individuals with obsessive–compulsive disorder (OCD), yet a substantial number of individuals with OCD do not fully respond to this intervention. Based on emerging experimental and clinical research on acceptance, this study sought to explore whether willingness to experience unpleasant thoughts, emotions, and bodily sensations during ERP was associated with improved treatment response. Methods Two hundred eighty‐eight adults with OCD receiving residential ERP provided self‐rated willingness and other exposure‐related variables during each daily coached ERP session. Obsessive–compulsive and depressive symptom severity was assessed every week. Multilevel modeling was used to study the impact of willingness on treatment outcome during the first 6 weeks of residential care. Results Data indicated that individuals with higher willingness during ERP reported faster symptom reduction during residential treatment, even when controlling for length of stay, psychopharmacological intervention, depression, adherence, and rituals performed during ERP. These results appear to have both statistical and clinical significance. Conclusions Willingness to fully experience unpleasant and unwanted thoughts, emotions, and bodily sensations during exposures appears to be a marker of successful exposure therapy in adults with OCD. Future research should examine how willingness may enhance extinction learning during ERP.