he authors investigated whether sex-specific norms should be used to assess symptoms of attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) in girls. It was hypothesized that (a) there would be a group of girls who exhibit ADHD or ODD symptoms using sex-specific norms but not using Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) criteria; (b) these girls would be significantly impaired relative to typically developing girls. These hypotheses were examined using behavior ratings completed by mothers and teachers of 1,491 elementary school students. Results showed that there was a small group of girls who did not meet DSM-IV criteria for ADHD or ODD but who had elevated ADHD and ODD scores when sex-specific norms were used. The same was not true for boys. The girls identified with sex-specific norms were more impaired than other girls. These results suggest that there may be a small number of girls who have behaviors and impairment that are consistent with ADHD and ODD, but they are not currently being identified by DSM-IV criteria.