We introduce a novel test of racial assignment that has significant implications for how racial categories are popularly understood, even among the populations for whom they purportedly apply. We test whether the U.S. Census Bureau’s definition of Asian corresponds with Americans’ understanding of the category, and find a disjuncture between those groups the U.S. government assign as Asian, and those that Americans include in the category. For White, Black, Latino, and most Asian Americans, the default for Asian is East Asian. While South Asians – such as Indians and Pakistanis – classify themselves as Asian, other Americans are significantly less likely to do so, reflecting patterns of “South Asian exclusion” and “racial assignment incongruity”. College-educated, younger Americans, however, are more inclusive in who counts as Asian, indicating that despite the cultural lag, the social norms of racial assignment are mutable. We discuss how disjunctures in racial assignment bias narratives of Asian Americans.