Significant ethnic differences have been consistently documented on attention-deficit/hyperactivity disorder (ADHD) teacher rating scales. Whether these ethnic differences result from a teacher rating bias or reflect actual classroom behavior patterns is unknown. Ethnic differences between Caucasian and African American (AA) elementary schoolchildren on teacher ratings and codings of observed classroom behavior were examined with latent variables. In structural equation models, correlations between teacher ratings and observed classroom behavior suggested nonbiased teacher ratings of AA schoolchildren with diagnosed ADHD. Ethnic differences were documented for both teacher ratings of ADHD and classroom behavior. Differences in classroom behavior were attenuated when the behavior of an average child in the classroom was taken into account. Multiple explanations for this pattern of results are discussed.