Speaking is one of the most challenging skills in studying English, raising concerns among many English teachers about how to help improve their students’ speaking performance. While many shy students prefer to work individually, others indicate their competence in group work. Therefore, this study investigates the effect of group discussion in authentic role-play on the speaking performance of English as a Foreign Language (EFL) young learners at a suburban primary school in the Mekong Delta, Vietnam. Participants in this study include 80 students: an experimental group (N=40) and a control group (N=40). During six weeks of the role-play session, experimental group students will work in groups, whereas the control group’s participants will prepare individually. Pre-tests and post-tests were employed to examine the students’ speaking performance, and interviews are conducted to compare students’ perceptions of the two role-play formats. The results from the speaking test show that the scores of the experimental group were higher than those of the control group. In the experimental group, five components are improved: pronunciation, content, vocabulary, grammar, and fluency. In contrast, only three components (pronunciation, content, and grammar) are enhanced in the control group. The findings from the interviews revealed that students of both group discussion and individual work engaged in role-play activities and substantially improved their language skills. However, they also faced some challenges in effectively using the two formats of role-play during speaking lessons.