This study explores the effectiveness of applying “Readers’ Theater” (RT) as English remedial instruction for underachievers. The participants of this study are 35 English underachiever students from a university of science and technology in northern Taiwan. Each participant receives two hours of weekly English remedial instruction for one year. The purpose of this study is to explore the impacts of RT on English oral reading, learning achievements, and learning attitudes of English underachievers. Quantitative data such as oral fluency assessment, English grades for the semester, as well as pre- and post- test English self-efficacy, English learning anxiety, and English learning motivation questionnaires are analyzed by using paired-sample t-test. The results of the study indicate that RT can enhance the oral reading ability, English learning ability, English self-efficacy, and English learning motivation of underachievers and reduce their English learning anxieties. Meanwhile, English self-efficacy can effectively predict the participants’ English learning achievements. In addition, teachers can use diverse and stimulating teaching strategies in conjunction with a warm and supportive learning environment to enhance the effectiveness of RT. Finally, the researchers propose recommendations for teaching and follow-up studies based on the findings of this research
