The history of Mexican American school segregation is complex, often misunderstood, and currently unresolved. The literature suggests that Mexican Americans experienced de facto segregation because it was local custom and never sanctioned at the state level in the American Southwest. However, the same literature suggests that Mexican Americans experienced de jure segregation because school officials implemented various policies that had the intended effect of segregating Mexican Americans. Ruben Donato and Jarrod S. Hanson argue in this article that although Mexican Americans were legally categorized as "White," the American public did not recognize the category and treated Mexican Americans as socially "colored" in their schools and communities. Second, although there were no state statutes that sanctioned the segregation of Mexican Americans, it was a widespread trend in the American Southwest. Finally, policies and practices historically implemented by school officials and boards of education should retroactively be considered de jure segregation. (Contains 11 notes and 1 table.)