: Steel-reinforced squat walls are used as the main component for earthquake resistance in low-rise structures. Given the low aspect ratio of squat walls, their behavior is dominating by inelastic shear deformations activated by the yielding of flexural reinforcement. These deformations degrade strength and stiffness with subsequent shear failure, preventing the wall from achieving its flexural capacity, which is a prerequisite for adequate seismic design. The available experimental studies on mid-rise shear walls show that the glass-fiber-reinforced-polymer (GFRP) reinforcement can control shear deformation, which is a major problem with steel-reinforced squat walls. Two full-scale squat walls with an aspect ratio of 1.3 were constructed and tested to failure under quasi-static reversed cyclic lateral loading: one was reinforced with steel bars; the other with GFRP bars. The experimental results show that the GFRP-reinforced wall evidenced significantly enhanced behavior related to ultimate strength, drift ratio, and mode of failure compared to the steel-reinforced wall.