This study used a mixed-method approach to investigate the effectiveness of Readers Theater (RT) in promoting English as a foreign language children's reading and writing proficiency after a participation period of one semester. In addition, the researcher recorded and analyzed children's learning motivation and feedback toward RT. The quantitative results of the study indicate that the RT group outperformed the control group in reading accuracy and fluency but not in reading comprehension. In writing performance, the researcher found significant differences for most aspects of writing proficiency, except for sentence structure. The qualitative results, on the other hand, support the idea that with RT, students have a purpose to interact in class, to work with others, to read and write for an audience, and, at the same time, enjoy their learning.