This best-evidence synthesis reviews the past 20 years of rigorous reading intervention research to identify effective programs of instruction for Grade K-3 English Learners (ELs), as well as to determine the average effect of reading instruction on reading outcomes for this population. We identified 10 studies, all of which only included students in Grades K, 1, and/or 2. These studies evaluated the effects of seven programs, reporting 76 effect sizes. We did not identify any studies that included Grade 3 ELs. To guide researchers and practitioners, we describe each program and discuss associated effect sizes in foundational skills, fluency, comprehension, and oral language. "Proactive Reading," delivered in a small group setting, produced some of the largest effects on foundational skills, fluency, and reading comprehension outcomes. "Sound Partners" was also shown to be effective even when delivered for a shorter duration, in a one-to-one setting. Finally, for practitioners and researchers aiming to improve oral language outcomes, "Early Vocabulary Connection," delivered to small groups of students for 20 weeks, had the largest effects on oral language outcome measures. The primary limitation of this review was the small number of studies meeting the best-evidence synthesis criteria. Future research is needed to better understand the impact of reading interventions on reading outcomes for ELs in Grades 2-3 and the impact of meaning-focused intervention on reading outcomes. In particular, additional research is needed to identify interventions that have the potential to meaningfully improve reading comprehension and oral language outcomes for K-3 ELs.