Slope stability remains a fundamental concern in geotechnical engineering due to its direct impact on structural safety and the longevity of civil infrastructure. In this study, a two-dimensional finite element method (FEM) is employed to investigate the influence of geogrid reinforcement distribution on the development of shear failure surfaces and the overall stability of a soil slope subjected to both gravitational and seismic forces. The model considers a slope with a height of 10 m and an inclination angle of 60° from the horizontal plane. Seismic loading conditions are incorporated using the pseudo-static method, wherein the horizontal seismic acceleration coefficient (kh) is varied from 0.1 to 0.4 to simulate different levels of seismic intensity. To assess the stability of the slope, the strength reduction technique is utilized, integrating both lower-bound and upper-bound analyses to compute the factor of safety (FOS) under various reinforcement and loading scenarios. The results reveal that the implementation of primary geogrid reinforcement layers is adequate for maintaining slope stability under both static and dynamic conditions. Additionally, the study provides a detailed comparison of the failure mechanisms observed in unreinforced and geogrid-reinforced slopes, offering valuable insights into the reinforcement’s effectiveness and the evolution of potential failure surfaces under seismic excitation.