AbstractSteel Plate Shear Walls (SPSW) have been used as a lateral-load-resisting system in buildings. With formation of tension fields, unstiffened SPSW possesses good ductility and high energy dissipating capability under cyclic loading. However, large demand is induced to the frame members from panel yielding. For typical frame configurations, very thin panels are often required to limit such demand but sometimes result in construction difficulties. This paper attempts to reduce such demand by introducing perforations to thicker panels. The effect on stiffness and strength is investigated through nonlinear finite element technique. Based on results described in this paper a simple linear reduction function is proposed.