Past studies have noted that black students' classroom behavior is rated more favorably by black teachers than by white teachers. This pattern could be a function of white teachers' bias--rating black students more harshly than they deserve--or black students' misbehavior--acting out more when placed with white teachers versus black teachers. If explanations emphasizing black students' misbehavior (oppositional culture) are accurate, matching effects should be more substantial among adolescents than among young children. To assess this possibility, the authors estimated matching effects among kindergartners in the Early Childhood Longitudinal Study--Kindergarten Class of 1998-99 and eighth graders from the National Education Longitudinal Study of 1988. They found that the effects of matching are comparable across both kindergartners and adolescents, a pattern that is more readily understood from the position of white teachers' bias than from that of oppositional culture.