A diathesis-stress perspective of obsessive–compulsive symptoms (OCS) predicts that exposure to adverse events and personality dispositions jointly influence OCS. Gray and McNaughton's (2000) model of personality posits that, faced with challenging circumstances, individuals with a high sensitivity to punishment (SP) will be more prone to OCS because they cannot avoid the downward spiral into anxiety. The current study investigates OCS severity in relation to lifetime exposure to adverse events (AE), SP, and sensitivity to reward (SR) in 122 nonclinical adults. The results indicate that OCS severity is predicted by AE, SP and SR. Interestingly, the impact of adverse experiences is moderated by SR and not SP. These findings suggest that: (1) exposure to adverse events and SP are independent OCS risk factors, and (2) exposure to adverse events is more critical for reward dependent people. This is discussed in light of responsibility and ‘not just right experiences’ in OCS, along with the role of impulsivity in the obsessive-compulsive disorder spectrum.