Children's emotion regulation strategies and parenting responses in a family task that elicited frustration are investigated by comparing core attention-deficit/hyperactivity disorder (AD/HD) symptomatology, emotional reactivity, and emotional regulation in the prediction of social behaviors and peer social preference. Participants were boys, ages 6-12 years, either with AD/HD (n = 45) or without problem behaviors (comparison; n = 34). A high-aggressive subgroup of AD/HD boys showed a significantly less constructive pattern of emotional coping than did both a low-aggressive AD/HD subgroup of boys and nondiagnosed comparison boys, who did not differ. With statistical control of core AD/HD symptomatology, noncompliance in a naturalistic summer camp was predicted by boys' overall emotion regulation and three specific strategies (emotional accommodation, problem solving, negative responses) during the parent-child interaction. Emotional accommodation and negative responses to the frustration task also marginally predicted social preference at the camp. These emotion regulation variables outperformed emotional reactivity in predicting such outcomes. Some emotion-related parenting behaviors were associated with child coping in the task. We discuss the relationship of emotion regulation to core AD/HD symptomatology and emotional reactivity, and the role of parents' behaviors in influencing children's emotional responses.