In this longitudinal study, we examined whether children differ in their susceptibility to harsh and responsive parenting as reflected in their externalizing and prosocial behaviour two years later. We focused on three potential susceptibility markers assessed during middle childhood: Negative emotionality, impulsivity, and effortful control. Participants were 120 Dutch children (6-11 years old; 54% girls). Parenting was assessed using both observations and self-report questionnaires. Parental responsiveness predicted decreased externalizing behaviour two years later among children high on impulsivity (in case of observed responsiveness) or low on effortful control (in case of observed and self-reported responsiveness) but not among children low on impulsivity or high on effortful control. Observed harsh parenting predicted decreased prosocial behaviour, especially among children with average or high negative emotionality. The findings support a diathesis-stress model more than they do a differential susceptibility model. High impulsivity seemed to be a vulnerability factor, predicting increased externalizing behaviour when parents lacked responsiveness. Also, high negative emotionality served as a vulnerability factor, predicting decreased prosocial behaviour when parents were harsh, while low negative emotionality served as a protective factor, buffering against decreased prosocial behaviour. Finally, low effortful control might operate as a vantage-sensitivity factor, predicting decreased externalizing behaviour when parents were responsive.