Astronomy education is essential for STEM education in primary schools, and integrating engineering design-based science education enhances student engagement and achievement in the field of space science. Integrating engineering design into science education is essential for students to excel in astronomy and to meet the requirements of contemporary society. This study investigated the effect of engineering design-based instruction (EDBI) on the understanding of astronomy concepts among sixth-grade students. The study included a cohort of 37 sixth-grade students from a public school. It was carried out using a one-group pre-test, post-test experimental design. All participants received EDBI that was based on the objectives of the 6th grade "Solar System and Eclipses" unit. Statistical analyses were employed to ascertain the effect of astronomy instruction based on engineering design on students' comprehension of astronomy concepts. The results indicated a significant difference in the average scores of students' understanding of astronomical concepts before and after being taught using EDBI.