Red mud, a by-product of alumina production through the Bayer process, is generated in large volumes and presents a serious environmental burden due to its strong alkalinity and limited reuse potential. Its low strength and high moisture retention restrict its direct application in civil engineering works, particularly as a subgrade material in pavements. To address this, the present study examines the potential of geogrid reinforcement to enhance the load bearing resistance of red mud for pavement applications. Two types of geogrids with identical aperture areas but different shapes, namely square and triangular, were manufactured using 3D printing technology. A series of laboratory California Bearing Ratio (CBR) tests under soaked conditions were conducted on unreinforced red mud and reinforced red mud with the geogrid of different aperture openings. The findings show that while square geogrid reinforcement improved the soaked CBR of red mud from 6.1% to 12.3%, the triangular geogrid achieved a significantly higher CBR of 17%. Resistance factor analysis further confirmed the superior performance of the triangular geogrid, with values of 3.53 compared to 2.51 for the square geogrid. The improved behavior with triangular geogrid is linked to its enhanced confinement and interlock efficiency with red mud particles. This study demonstrates that red mud reinforced with geogrid can be effectively used in pavement construction, contributing to sustainable practice by means of offering a cost-efficient approach to manage the industrial waste.