It is well-documented that there is a strong relationship between vocabulary and reading comprehension in school-age children. Limited vocabulary knowledge can impact a student’s reading achievement, as may be the case for school-age English Learners (ELs). This study aims to analyze the role of vocabulary in predicting reading comprehension outcomes of English/Spanish emergent bilingual EL students. Secondary data analysis was conducted using a subset of longitudinal data collected as part of a federally funded grant. Analyses included two cohorts of elementary school students in dual immersion programs and examined their performance on vocabulary measures in English and Spanish and reading achievement in English. During the first wave of data collection, students were in first grade (n=63; Cohort 1) and third grade (n=61; Cohort 3). Descriptive statistics, correlations, and group means were examined for the differences in vocabulary and reading achievement between time points within each cohort of students. Hierarchical linear regressions reported the amount of variance that expressive and receptive vocabulary in English and Spanish contributed as predictors of English reading comprehension among each cohort of emergent bilingual students. Findings and implications are discussed.