To assist effectively with social difficulties, parents must accurately understand the peer situations that are difficult for their child. Mothers’ insight into their young adolescent's vulnerability to friendship jealousy was assessed by posing identical vignettes to 72 young adolescents and their mothers and matching their responses. Mothers and children also completed questionnaires on their relationship and the child's adjustment. Mothers as a group were poor judges of their child's jealousy, but considerable variability existed. Accuracy was greater when mother–child pairs were closer. Polynomial regression and response surface analyses indicated that maternal accuracy could dampen the friendship and aggression risks otherwise associated with being vulnerable to jealousy.