"Brown v. Board of Education" (1954) was a landmark decision that was the result of decades of efforts by grassroots activists and civil rights organizations to end legalized segregation. A less well-known effort challenged the extralegal segregation of Mexican American students in the Southwest. I combine original research and research synthesis to explore the connections between these legal campaigns. Three key differences between African American and Mexican American segregation had important implications for the legal strategies in the latter: (a) de jure versus extralegal segregation; (b) the legal whiteness of Mexican Americans; and (c) the racialization of language. While both sets of lawsuits drew on social science research to challenge segregation, differences in timing and legal arguments seem to have prevented sustained connections between the two efforts.