Previous studies have implicated migration and ethnicity as possible risk factors for autism spectrum disorder (ASD) in developed countries. Using Texas education data, we calculated district-reported ASD prevalence stratified by geographic region, with reported home language as a proxy for immigration. Prevalence ratios were also stratified by race. Prevalence estimates were significantly lower for White children from homes speaking Spanish and other non-English languages compared to those from English-speaking homes. This is the first study, to our knowledge, that investigates ASD prevalence of children from non-English-speaking households in a large sample. Barriers in identification of children of immigrants with ASD indicate that the increased district-reported prevalence seen in our study may only be a small indicator of a potentially larger prevalence.