BASC-2 SRP-A scores of 162 American Indian (AI) youth were compared with those of an ethnically diverse sample (N = 200) to explore group equivalence. A MANOVA indicated group differences among the five composites. AIs outscored non-Natives in Inattention/Hyperactivity. We examined AIs' ADHD scores in relation to their acculturation strategies, measured using the Bicultural Ethnic Identity Scale. Culturally marginalized AIs (low White and low Indian acculturation) reported stronger ADHD symptoms than bicultural, assimilated, or separated youth. The potential impact of culture on clinical measures is discussed.