The error-related negativity (ERN), an event-related potential component elicited by error responses in cognitive tasks, has been shown to be abnormal in most, but not all, studies of obsessive–compulsive disorder or obsessive–compulsive symptoms (OCD/S); these inconsistencies may be due to task selection, symptom subtype, or both. We used meta-analysis to further characterize the ERN in OCD/S, and pooled data across studies to examine the ERN in OCD/S with hoarding. We found an enhanced ERN in OCD/S relative to controls, as well as heterogeneity across tasks. When stratified, OCD/S showed a significantly enhanced ERN only in response conflict tasks. However, OCD/S + hoarding showed a marginally larger ERN than OCD/S–hoarding, but only for probabilistic learning tasks. These results suggest that abnormal ERN in OCD/S is task-dependent, and that OCD/S + hoarding show different ERN activity from OCD/S - hoarding perhaps suggesting different pathophysiological mechanisms of error monitoring.