The authors examined disparities in special education labeling among children diagnosed with attention-deficit/hyperactivity disorder (ADHD) by merging calendar year 2002 special education records and Medicaid mental health claims for 4,852 children who had been diagnosed with ADHD in Philadelphia, Pennsylvania. Thirty-eight percent were receiving special education services. In adjusted analyses, Black children were less likely than White children to receive these services (odds ratio [O.R.] = 0.78); among the children in special education, Black children were more likely to have the emotional disturbance (ED) label (O.R. = 1.40). There was a significant interaction between ethnicity and receipt of behavioral health and rehabilitation services (BHRS): White children with BHRS were more likely to be in special education than were White children without BHRS or Black children. Among the children in special education, White children with BHRS and Black children were more likely than White children without BHRS to be labeled ED. The results indicate ethnic disparities in special education labeling among children with similar clinical profiles and that mental health and education services are substituted for each other differently based on ethnicity. Possible reasons include undertreatment of ADHD, differential interpretation of associated behaviors, and differences in parents' ability to advocate for children's educational and mental health needs. (Contains 2 tables and 1 figure.)