Reciprocal teaching was introduced in 1984 by Palincsar and Brown. However, in Vietnam, it remains a new method that is still unfamiliar to many primary school teachers. Conducting an experimental study on its effectiveness on Vietnamese primary students' reading comprehension is essential, especially as the country is undergoing educational reform from primary to high school levels. A mixed-methods study lasting 8 weeks was conducted with 144 third-grade students in Vietnam. Data collection tools included a reading comprehension test to assess students' pre- and post-intervention performance, and observation checklists completed by 4 observers to measure the fidelity of teachers' implementation during the experiment. The observers also provided their perspectives on how the experimental group teachers applied the method in their classrooms. In terms of quantitative data, a t-test was used to analyze the differences in reading comprehension test scores between the experimental and control groups. Statistical analysis was also used to assess the fidelity of teachers' implementation of reciprocal teaching in their classrooms. In addition, qualitative content analysis was conducted to evaluate the advantages and disadvantages of the intervention. A t-test showed the experimental group scored significantly higher in reading comprehension (t(142) = -6.07, p < 0.001). Statistical analysis indicated that all experimental teachers received a rating of “good” (level 3 or above) on a 4-point scale. Meanwhile, qualitative findings highlighted challenges faced by teachers, such as managing large class sizes and guiding students through the summarizing strategy. Based on the study’s findings, several recommendations are provided for researchers and educators.

Keywords: Reciprocal teaching, primary students, reading comprehension, experimental, observation.