Parents’ beliefs that emotions should be controlled (valuing emotion control) have been connected to worse parent-child relationship outcomes. The current work longitudinally investigated how the relationship between valuing emotion control and parent-child outcomes (relationship quality and well-being) is mediated by parents’ unsupportive responses to their children’s emotions. We found that parents’ valuing emotion control predicted lower parent-child relationship quality (𝜷 = -0.17, SE= 0.04,p < .001) and poorer child well-being (𝜷 = -0.18,SE= 0.04, p < .001). This was mediated by parents’ unsupportive responses such that parents’ valuing emotion control predicted more unsupportive responses which in turn predicted lower relationship quality (indirect effect = -0.06 [-0.14, -0.01]) and poorer child well-being (indirect effect = -0.05 [-0.11, -0.01]). Overall, valuing emotion control may negatively impact responses to others’ emotions and subsequently the perceived relationship quality as well as the other person’s well-being.