Research on parental monitoring of children's media use suggests parents can reduce the negative effects of media exposure on children, although this research is rarely conducted with elementary school children and leaves open questions about whether parents or children are better reporters. Participants were 1,323 children, their parents, and teachers. Parents and children reported on four aspects of monitoring for TV and video games: co-using, limit setting on amount, limit setting on content, and active mediation. Parents gave much higher estimates than did children. Monitoring was moderated by child age, child sex, parent marital status, parent education, and parent income. Although parent- and child-reported monitoring correlated rather poorly, both types were almost equally good predictors of children's screen time, media violence exposure, and teacher reports of school performance. When there were differences, the child reports tended to be slightly better predictors, demonstrating the validity of child reports of parental monitoring.