Abstract: Recent experimental results have demonstrated the great advantages of strengthening or rehabilitating structures using Steel Fiber Reinforced Concrete (SFRC). This paper presents both the experimental and numerical results on the out-of-plane behavior of un-reinforced masonry walls strengthened with SFRC overlays. Four un-reinforced masonry walls strengthened with 1.0%, 1.5%, 2.0% and 2.5% volume fractions of steel fiber reinforced mortar were tested. It was found that the optimistic volume fraction of steel fibers used for strengthening un-reinforced masonry walls was 1.5%. Numerical simulations are compared with experimental results, and the proposed model simulates the ultimate load capacity of the strengthened wall well.