The goals of this study were to evaluate the impact of a supplemental preschool intervention on Spanish-speaking English language learners’ (ELLs) phonological awareness (PA) and vocabulary skills and to examine the associations between these skills in both languages. Participants included 30 Head Start preschoolers. Of these, 18 were randomly assigned to receive the intervention in Spanish or English, and 12 served as controls. Based on our hypotheses, we computed one-and two-tailed t -tests to analyze and compare gains from fall to spring. Associations between children’s PA skills and between their vocabulary skills in Spanish and English were analyzed using correlation analyses. Results indicated that children in the intervention group achieved greater gains in PA and vocabulary than did the controls. Children who received Spanish intervention displayed equivalent or greater gains on all measures than children who received English intervention. Results also revealed significant relationships between PA skills in Spanish and English and moderate to strong relationships between receptive vocabulary in Spanish and English. Results support the positive role that speech-language pathologists can play in preschoolers’ language and early literacy development and the importance of considering the interrelationships between both languages when planning intervention for ELLs.