The present study aimed to investigate the effectiveness of sensory integration-based intervention on handwriting problems of slow-paced students. The study method was a quasi-experimental pre-test and post-test with a control group. The statistical population of the present study consisted of all slow-paced elementary school students studying in special schools in Qom city with the age range of 10 to 13 years in the Fourth to sixth grades of elementary school. A multi-stage cluster method was used to select the sample, and finally, 30 students were selected based on the study entry criteria, and they were randomly assigned to two experimental and control groups. Then, the intervention program (sensory stimulation related to the sensory integration method and perceptual-motor training based on Jennickson's Building Blocks for Learning program; Translated by Faramarzi, 2025) was carried out on the experimental group for ten sessions individually and weekly. The results of the study showed that the sensory integration-based intervention significantly (P<0.0001 and F=9.751) at a significance level of 0.05 improved the writing performance of slow-paced students in the experimental group compared to the control group. The findings of the study indicated that sensory integration exercises can improve the handwriting problems of slow-paced students in the components of readability, handwriting, writing speed, pressure on the pen and paper, separation of writing, and the direction of pencil movement, and the sensory integration training package can be used as an appropriate intervention in improving the handwriting skills of slow-paced students.