The paper aimed at examining how the use of the Know - Want to Know - Learned (KWL) strategy affected fifth-graders’ reading comprehension achievement at Vstar School in Ho Chi Minh City. To achieve the aim of the study, the researcher employed a quantitative approach with a two-group quasi-experimental pretest-posttest design. Data was collected via a questionnaire, a pretest, and a posttest conducted on 50 students of two fifth-grade classes (N=25 for each class) which were conveniently chosen from 270 fifth-graders at Vstar School. The research results indicated statistically significant differences in reading comprehension achievement of the experimental class between the pretest and the posttest with better results found in the posttest. Additionally, there were also statistically significant differences between the control class and the experimental class after the application of the KWL strategy. Based on the findings, some recommendations were suggested to teachers of English, students learning English as a foreign language (EFL), and researchers having an interest in the topic.