Shear walls reinforced with glass fiber-reinforced polymer (GFRP) are a corrosion-free lateral resisting system transparent to magnetic fields and radio frequencies and nonconductive thermally and electrically. Recently, limited research has demonstrated an acceptable seismic response of GFRP reinforced shear walls. However, significant research is still required to fully understand their behavior and implement such elements in construction. The present numerical study addresses the effect of different parameters on the seismic response of GFRP-reinforced shear walls. A numerical macro-model is developed using OpenSees to simulate the in-plane response of flexure-dominated reinforced RC shear walls with boundary elements. The model was validated against experimentally tested walls from the literature. A numerical study is performed on eight flexure-dominated shear walls to evaluate the influence of different design parameters on the inelastic behavior under quasi-static fully reversed cyclic loading. The investigated parameters are transverse hoop spacing, vertical reinforcement in the boundary element, and GFRP vs. steel reinforcement. The influence of the design parameters on the hysteretic response, stiffness degradation, and effective stiffness was investigated to evaluate the enhancement in the seismic performance.