This article examines the emergence of Mexican American school segregation from 1915 to 1935 in Kansas, the state that gave rise to "Brown v. Board of Education" in 1954. Even though Mexicans were not referenced in Kansas's school segregation laws, they were seen and treated as a racially distinct group. White parents and civic organizations pushed school officials to establish separate facilities for Mexican children. We argue that the contradictory and enigmatic responses to school segregation from high-ranking U.S. and Mexican government officials pointed to a degree of uncertainty about whether Mexican children could be segregated. That ambiguity, however, did not prevent local school officials from placing Mexican children in separate facilities. As the American Educational Research Association continues to pursue education research that promotes the public good, the segregation and resegregation of Mexican children in the United States must be framed as a critical issue moving forward into the "next 100 years."