Recently, the construction of Narrow Mechanically Stabilized Earth (NMSE) Walls of aspect ratio (ratio of reinforcement length, L, to wall height, H) below 0.7 is needed in developing urban areas. NMSE walls are subjected to seismic ground excitation when constructed in active seismically areas. This investigation focuses on the behavior of rigid NMSE walls based on reduced-scale shaking table tests. This involves performing three small 1-dimensional shaking table tests, 1/8 of the prototype model. The models are excited using stepped amplitude sinusoidal base accelerations with incrementally increasing displacement amplitude and constant frequencies to generate an equivalent base acceleration ranging from 0.05g to 0.7g or until failure. The models have an aspect ratio, L/H, 0.4 and the ground motions predominant frequencies are assumed to be 1, 2.5 and 5 Hz. The results show shat increasing the predominant frequency from 1 to 5 Hz reduces the critical accelerations from 0.4g to 0.2g, respectively. Also, the results show that the critical acceleration is highly sensitive to the input motion predominant frequency. Consequently, the maximum design acceleration proposed by pseudo-static design method (0.3g) isn't agreement with this study.