This longitudinal study investigated 196 Hispanic English learners' responses to an English instructional intervention from kindergarten to second grade. The effect of student gender was also examined as a secondary focus. The intervention consisted of ongoing professional development and structured and systematic English intervention during an English as a second language (ESL) block. A multilevel modeling approach revealed that (a) the intervention effect was positive and significant, reflecting a range of phonological awareness, oral language skills, and decoding and reading proficiency, indicating the effectiveness of this intervention, and (b) that boys possessed more expressive vocabulary knowledge upon school entry and acquired receptive vocabulary faster than girls, while both girls and boys attained comparable levels of decoding skills and reading proficiency. We conclude that the effect of instructional intervention is stronger than the effect of gender. More well-planned, scientifically based research is needed to promote the linguistic development of English learners.