Objective: To examine how constructiveness in interparental conflict affects mothers’ perception of children’s psychological and physical health, and whether coparenting and positive parenting mediate these effects. Background: Children exposed to high levels of interparental conflict are at elevated risk to develop health problems. However, previous research suggests that constructive and destructive interparental conflict may affect children’s health differently. Method: 289 mothers with at least one child aged 3.5 to 8 years completed an online survey about parenting, coparenting, interparental conflict, and different aspects of child health. Results: Results suggest that higher constructiveness in interparental conflict is related to fewer emotional problems, less pain, and fewer infectious diseases in children, independent of gender. The effects were fully mediated by coparenting. Conclusion: Constructive interparental conflict promotes children’s physical and psychological health and coparenting emerged as an important mechanism for this link. Implications: Enhancement of constructive interparental conflict and coparenting are promising avenues to foster children’s healthy development.