Adverse life events increase the risk of obsessive-compulsive disorder (OCD). Parental rearing may serve as a protective factor in the face of adversity. We investigated whether parental rearing moderates the association between adverse life events and the subsequent first onset of OCD. A representative sample of individuals (aged 14–24 years) was followed for over 10 years (N = 2210). OCD and any adverse life event, that is, any separation event or any traumatic life event, were assessed using the Munich-Composite International Diagnostic Interview. Parental rearing was assessed by self-report, using the Questionnaire of Recalled Parental Rearing Behavior. Both maternal (risk ratio, RR = 0.08, 95% confidence interval, CI [0.02, 0.31]) and paternal (RR = 0.16, 95% CI [0.03, 0.89]) emotional warmth moderated the association between any adverse life event and OCD. Maternal (RR = 0.16, 95% CI [0.03, 0.77]) and paternal (RR = 0.17, 95% CI [0.04, 0.78]) emotional warmth interacted specifically with any traumatic life event but not with any separation event in predicting OCD. We did not find any interactions with parental overprotection or rejection in predicting OCD. Parental emotional warmth may be a protective factor for OCD among individuals who experience traumatic life events. Future studies should evaluate whether interventions enhancing parental emotional warmth among those who experience traumatic life events can prevent OCD.