Ensuring the safety of slopes is a critical issue because of its profound implications for infrastructure, environmental protection, human safety, and disaster risk reduction. Among the factors influencing slope instability, groundwater level is particularly significant, as variations in moisture content can alter the soil's strength, leading to an increased risk of failure. This paper will investigate how groundwater impacts the effectiveness of root reinforcement for slope stabilization, emphasizing key parameters of root cohesion and thickness of root zone. Additionally, the study will compare results from both the Finite Element Method (FEM) and the Limit Equilibrium Method (LEM) to assess their relative effectiveness in modeling root-reinforced slopes under different groundwater conditions. The results indicate that more significant increase of factor of safety (FS) observed when Hw/H = 0 compared to Hw/H = 0.5. The greatest FS is achieved with thickness of root zone of 1.5 m and a root cohesion of 20 kPa, with less than a 1% difference in FS between low and high groundwater levels in this optimal case. Additionally, FS enhancement calculated using the LEM is nearly double that obtained with the FEM.