The objective of this research is to study experimentally the effect of rice straw fibers on slope stability. A sand box model was used to simulate the slope failure mechanism under reinforced and unreinforced soil using rice straw fibers. Analysis takes into account three factors; Slope angle (β), load edge distance from loading plate edge (X), and percentage of rice straw. Constant water contents were used in all experiments. Laboratory results showed that soil stress increases significantly by increasing the percentage of rice straw fibers up to 0.75% by weight of sand soil