Weak subgrade soils can adversely affect pavement performance by reducing the load-bearing capacity of the foundation and increasing the possibility of deformation under traffic loading. This study investigates the use of geogrid reinforcement for improving the California Bearing Ratio (CBR) of different subgrade soils. Sixteen soil samples representing highly compressible clay, intermediate compressible clay, low compressible clay, and sandy soils were examined. Natural and synthetic geogrids, including coir, jute, rubber coir, polyester, biaxial polypropylene, biaxial geogrid, and HDPE geogrids, were evaluated at different depths within the CBR mould. The influence of the optimum moisture content, maximum dry density and liquid limit on the reinforced and unreinforced CBR values was also examined. The results show that geogrid reinforcement generally improves the CBR of the tested soils, although the extent of improvement varies with the soil type, reinforcement material, and placement depth. A placement depth of 0.8h produced considerable improvement for several soil samples. The highest CBR value of 12.8% was obtained for sandy soil reinforced with HDPE geogrid at a depth of 0.8h. The study also indicates that higher maximum dry density is generally associated with improved CBR, whereas excessive moisture can reduce soil strength. The findings demonstrate that selecting the appropriate geogrid and its placement depth can improve subgrade performance and may contribute to more economical pavement construction.