Objective: The present study aimed to determine the effectiveness of an RTI-based instructional program in improving procedural knowledge and conceptual understanding in students with mathematical learning disabilities.

Method: This research employed a quasi-experimental design with a pretest–posttest–follow-up and a control group. The statistical population consisted of fourth-grade male students with mathematical learning disabilities in Semnan during the 2023–2024 academic year. A voluntary sampling method was used, and after screening, 16 students were randomly assigned to the experimental and control groups (8 students in each group). The experimental group received an instructional program based on RTI over 18 thirty-five-minute sessions across six weeks, whereas and an active control group aimed at controlling nonspecific effects received a lower-intensity version over 5 sessions. Procedural knowledge and conceptual understanding were measured at three time points, and data were analyzed using repeated-measures MANOVA.

Results: The findings showed that the average scores of the experimental group compared to the control group in problem solving and addition, subtraction, multiplication, and division scores not only increased significantly in the post-test, but also the effects were stable until follow-up.

Conclusion: The RTI-based instructional approach is effective in improving procedural knowledge and conceptual understanding among students with mathematical learning disabilities and can be utilized in instructional programs tailored to their needs.