This study investigates bilingual performance on the English and Spanish Boston Naming Tests (BNTs) while controlling for object familiarity and U.S. acculturation. Previous studies suggest that bilingualism negatively affects naming skill; however, object familiarity, which may be culturally influenced, and U.S. acculturation level have not been formally investigated. The current sample comprised 74 well-acculturated bilinguals and 52 English monolinguals. Participants judged their familiarity with BNT objects and later named the objects in either English or Spanish. Both groups rated BNT objects to be comparably familiar. However, bilinguals underperformed relative to monolinguals. In fact, those bilinguals born and raised in the USA and educated solely under English instruction were unable to match monolinguals' superior naming performance. These results underscore a language disadvantage in naming even for native-born, highly acculturated, English proficient bilinguals and suggest that the BNT is language specific and perhaps unsuitable for testing bilingual populations.