As an effective teaching approach that allows teachers and students to interact collaboratively and actively build on each other’s ideas, dialogic teaching can enhance classroom engagement and learning outcomes. This study addresses the use of dialogic teaching for improving English language learning among Chinese children with varied levels of English vocabulary. It focuses on the effects of dialogic teaching on vocabulary knowledge and phonological awareness. Seventy-two first graders from Hong Kong primary schools were tested on English vocabulary knowledge and phonological awareness and were assigned to control and experimental conditions. A 12-week dialogic teaching intervention was implemented in daily English lessons. Results from repeated measures ANOVA showed that students in the experimental condition with dialogic teaching implemented exhibited significantly greater growth in expressive vocabulary knowledge on textbook items in both low and high vocabulary groups, and greater gain in phonological awareness in the high vocabulary group, than those in the control condition. These results suggest that dialogic teaching in English-as-a-second-language (ESL) classroom enhances English language development in young ESL learners. In addition, when assessing the effectiveness of dialogic teaching in young children’s second language classroom context, it is important to consider its differential effects on children with diverse vocabulary levels. Copyright © 2021 The Author(s).