This study aims to investigate the effectiveness of English vocabulary class using an augmented reality (AR) application for elementary school students’ cognitive (phonemic awareness and vocabulary ability) and affective (interest, self-confidence, and immersion) domains. Forty-one students participated in the class for 6 weeks (twice a week). Most of them were at a beginner level in English courses. The class for the experimental group (20) was taught using an AR technology and the control group (21) was operated using the traditional method of instruction. The research findings suggest that learning activities based on AR have statistically meaningful effects on enhancing phonemic awareness cognitively and self-confidence affectively. It is encouraging that English classes based the AR application can improve the cognitive and affective domains of young learners with low English skills. This study shows the educational potential and possibilities of learner-friendly AR technologies that can be practically applied to in education classes for elementary school students. Further studies are needed to design more effective teaching and learning models based on augmented reality platforms in English education.