ABSTRACT: Experimental investigation and numerical simulation are carried out to assess the behavior of unreinforced concrete masonry (URM) walls using Steel-Fiber Reinforced (SFR) high strength mortar, with a compressive strength of 60 MPa and 3% fiber by weight of cement, in the joints and the plaster. Three walls of 800 mm in length and width and 100 mm in thickness were made using hollow concrete blocks. The hollow block masonry walls were made with (1) normal strength mortar in the joints as control specimen, (2) high strength SFR mortar in the joints, (3) normal mortar in the joints plastered with high strength 10 mm thick SFR mortar. The walls were tested under constant vertical load with horizontal load in the form of in-plane cyclic loading. The damage progression in wall specimens and their failure modes were observed. The response of these Walls to a gradual increase in lateral load was recorded in the form of hysteretic load deflection curves. The experimental results show a significant increase in shear capacity of the wall plastered with SFR mortar. The wall constructed with SFR mortar in the joints showed better stability in the wall after failure, with a small increase in the shear capacity. Finite element modeling of the walls in the ABAQUS environment captured the lateral load-displacement response of the wall with good accuracy using the plastic damage model.