Background: The aim of this study was to explore perceptions of free will in the repetitive behaviors of patients with obsessive-compulsive disorder (OCD) and to explore their relation with core clinical characteristics. Methods: Experiences of free will were assessed with the Symptomatology And Perceived Free will rating scale (SAPF) in 295 subjects with a lifetime diagnosis of OCD. Patients' scores on the SAPF were subjected to an explorative principal axis factor analysis (PAF). Factor scores were regressed on five OCD symptom dimensions and on seven clinical variables: illness duration, severity of OCD, insight, anxiety and depression, suicidal ideation and quality of life. Results: The PAF revealed three factors: the perceived ability to control and change one's course of action when faced with an obsession or compulsion (the "alternative possibilities" factor); the experience of obsessions or compulsions as intentional (the "intentionality" factor); and the experience of being the source or owner of the obsessions or compulsions (the "ownership" factor). Lower scores on the "alternative possibilities" factor were associated with lower scores on the washing dimension (β = 0.237, p = 0.004) and higher scores on the precision dimension (β = - 0.190, p = 0.025) and independently associated with longer illness duration (β = - 0.134, p = 0.039), higher illness severity (β = - 0.298, p < 0.001) and lower quality of life (β = 0.172, p = 0.046). Lower scores on the "intentionality" factor were independently associated with lower quality of life (β = 0.233, p = 0.027). Higher scores on the "ownership" factor were associated with higher scores on the precision dimension (β = 0.207, p = 0.023) and independently associated with poorer insight (β = 0.170, p = 0.045). Conclusions: The most notable finding of this study is that a diminished experience of free will in OCD is associated with core clinical characteristics: illness duration and severity, insight and quality of life.