The dopamine active transporter 1 (DAT1) gene is implicated in psychopathology risk. Although the processes by which this gene exerts its effects on risk are poorly understood, a small body of research suggests that the DAT1 gene influences early emerging negative emotionality, a marker of children's psychopathology risk. As child negative emotionality evokes negative parenting practices, the DAT1 gene may also play a role in gene–environment correlations. To test this model, children (N = 365) were genotyped for the DAT1 gene and participated in standardized parent–child interaction tasks with their primary caregiver. The DAT1 gene 9-repeat variant was associated with child negative affect expressed toward the parent during parent–child interactions, and parents of children with a 9-repeat allele exhibited more hostility and lower guidance/engagement than parents of children without a 9-repeat allele. These gene–environment associations were partially mediated by child negative affect toward the parent. The findings implicate a specific polymorphism in eliciting negative parenting, suggesting that evocative associations play a role in elevating children's risk for emotional trajectories toward psychopathology risk.