This paper presents results from an investigation of the behavior of unstiffened thin steel plate shear wall (SPSW) having a regular pattern of openings (a.k.a. perforated SPSW). Finite element monotonic pushover analyses were conducted, first on a series of individual perforated strips with variation in perforation diameter, to develop a fundamental understanding of the behavior of complete perforated SPSW, then on a corresponding series of complete perforated SPSW having various perforation diameters. Three different sets of wall boundary conditions are considered, namely: flexible beam laterally braced, rigid floor, and rigid beam. Though some differences between the SPSW panel strips and the individual strip results are observed at large monitored strain, at lower monitored strain however the two models are in a good agreement. Based on the analytical results design recommendations of these perforated SPSWs are presented. The shear strength of a SPSW infill plate having a pattern of multiple regularly spaced circular perforations can be calculated as a function of the shear strength of a solid panel, perforation diameter, and distance between perforations.