Collaborative Strategic Reading (CSR) is a research-based instructional practice in teaching reading comprehension which combines comprehension and cooperative learning. This study investigated the effect of CSR on Iranian high school students’ reading comprehension. Using a quasi-experimental design, 60 female high school students were selected based on their scores on a language proficiency test and were grouped into two experimental and control groups (EG and CG). The CG had its conventional teacher-led context while the EG received CSR as the treatment. Their scores at the onset of the study were collected via a researcher-made comprehension pretest followed by a parallel posttest at the end of the treatment. To analyze the data, independent sample t-tests were run to compare the achievement of the two groups. A semi-structured interview was also conducted to investigate their attitudes toward the employment of CSR. The results showed a significant difference between EG and CG emphasizing the positive role of CSR in improving students’ comprehension. The findings of the interview also showed positive attitudes of the participants and the teacher on the feasibility of the model to help the learners. The results of the study could help material developers in designing more collaborative tasks, activities, assignments, and materials for EFL learners. پرونده مقاله