This study examined the impact of a 15-min daily explicit vocabulary intervention in Spanish on expressive and receptive vocabulary knowledge and oral reading fluency in Spanish, and on language proficiency in English. Fifty Spanish-speaking English learners who received 90 min of Spanish reading instruction in an early transition model were randomly assigned to a treatment group (Vocabulary Enhanced Systematic and Explicit Teaching Routines [VE-SETR]) or a comparison group that received general vocabulary instruction using the standard reading curriculum with general strategies designed to increase the explicitness of instruction (General Systematic and Explicit Teaching Routines). Results indicated a statistically significant difference in depth of student Spanish vocabulary knowledge favoring the VE-SETR group. Differences on language proficiency in English, general vocabulary knowledge in Spanish, and oral reading fluency in Spanish were not statistically significant. Implications for future research are discussed.