Role-play is an oral classroom activity that has been promoted to provide young learners with opportunities to practice English in meaningful contexts. To familiarize elementary students with this group task, to encourage them to pay attention to their peers' performances, and to replace traditional paper-and-pencil modes of evaluating speaking tasks, an alternative group peer assessment (PA) was proposed in this action research implemented with 114 fourth-grade and fifth-grade students in four classes in an elementary school in southern Taiwan. Analyses of ratings and written comments of the teacher and peer groups, student survey, and teacher reflection showed PA served a possible approach to evaluate English learners' speaking performance. Students enjoyed and benefited from being empowered in their learning. Suggestions for future practice include emphasizing rationale for practicing PA, facilitating group discussions, explaining explicitly how to give and accept constructive comments, clarifying evaluation rubrics, and taking into account students' language abilities and learning styles.