Longstanding gaps between the reading achievement of English learner (EL) students and native English speakers highlight the need for evidence-based reading interventions validated for EL students. This study compared the efficacy of two flashcard-based interventions, incremental rehearsal (IR) and strategic incremental rehearsal (SIR), for teaching EL students high-frequency words. Using an adapted alternating-treatments single-case design, 8 students were exposed to IR, SIR, and a control condition. Participants were Spanish-speaking students in the elementary grades. Short-term (next session) retention, generalized text reading, and long-term retention (1–4 weeks) of words were assessed. Findings indicated that both approaches improved word reading over the control condition; however, the extent to which IR and SIR differed in their efficacy varied across each outcome and participant. The most consistent finding was that students’ long-term retention of words taught with SIR was higher than words taught with IR. Results have implications for the implementation of SIR with EL students. Limitations and future directions for research are discussed.