Acknowledging that the parent-child attachment is a dyadic relationship, we investigated differences between pairs of parents and preschool children based on gender configurations in the association between attachment and problem behavior. We looked at mother-daughter, mother-son, father-daughter, and father-son dyads, but also compared mothers and fathers, daughters and sons, and same versus different gender pairs. We employed multigroup structural equation modeling to explore moderation effects of gender in a sample of 446 independent pairs of parents and preschool children (2-5 years old) from the Netherlands. A stronger association between both secure and avoidant attachment and internalizing problems was found for father-son dyads compared to father-daughter dyads. A stronger association between both secure and avoidant attachment and externalizing problems was found for mother-son dyads compared to mother-daughter and father-daughter dyads. Sons showed a stronger negative association between secure attachment and externalizing problems, a stronger positive association between avoidant attachment and externalizing problems, and a stronger negative association between secure attachment and internalizing problems compared to daughters. These results provide evidence for gender moderation and demonstrate that a dyadic approach can reveal patterns of associations that would not be recognized if parent and child gender effects were assessed separately.