This study examined whether developmental patterns of inhibitory control (IC) and kindergarten math achievement differed among Head Start children with varying dual language learning status. This study further explored the potential mediation effects of IC development as an explanation of differences in kindergarten math skills across children with varying dual language learning status. Based on their English skills and home language use, children' dual language learning status was categorized into (1) Spanish-English bilingual children, (2) Spanish-English dual language learners with limited English skills (DLLs-LES), and (3) English-monolingual children. Analyses were conducted using data from the Head Start Family and Child Experiences Survey (FACES) 2009 Cohort. Results showed that bilingual children presented greater IC at Head Start entry than DLLs-LES and faster growth in IC through kindergarten (1.5 years) than English-monolingual children. Bilingual children also outperformed monolingual children and DLLs-LES in math at kindergarten, despite the fact that they had lower baseline math skills than monolingual children. DLLs-LES, on average, presented the lowest IC skills and math skills through kindergarten. DLLs-LES, however, presented faster growth in IC than English-monolingual children through kindergarten. The achievement gaps in math among the three groups were explained by relative differences in IC development among the groups. The current study with low-income preschoolers supported emerging literature suggesting the benefits of bilingualism for cognitive skills and learning. Study implications are discussed. (author abstract)