Geogrids are widely utilized geosynthetic materials designed to reinforce soil structures and enhance their mechanical performance. While cohesionless soils exhibit minimal tensile strength and are prone to shear failure under loading, geogrids possess high tensile strength, enabling them to redistribute stresses across a wider zone within the soil mass through interlocking and membrane mechanisms. This paper presents a numerical investigation into the bearing capacity of a shallow strip foundation on geogrid-reinforced sandy soil. A parametric study was conducted using finite element analysis to evaluate the influence of reinforcement layout parameters, specifically focusing on the normalized geogrid depth ((u/B)) and normalized geogrid width ((b/B)). The vertical spacing of the first geogrid layer relative to the foundation width ((u/B)) was varied between (0.25) and (1.0), while the normalized geogrid width ((b/B)) was investigated in the range of (1.0) to (15.0). The reinforcement efficiency was quantified using the non-dimensional Bearing Capacity Ratio ((BCR)), defined as the ratio of the ultimate bearing capacity of the reinforced soil to that of the unreinforced counterpart. The numerical results demonstrate that the installation of geogrid layers significantly enhances the bearing capacity of the sandy soil. However, the improvement rate diminishes asymptotically beyond certain threshold limits. The optimum reinforcement width was determined to be approximately (1.75) to (2.0) times the foundation width ((b/B \approx 1.75)–(2.0)). Beyond this optimal geometry, further increasing the width yields negligible increases in the ultimate bearing capacity. Similarly, the effectiveness of the reinforcement decreases as the depth of the first layer ((u/B)) increases beyond the critical threshold.