Masonry shear walls are one of the most common structural elements in buildings. The in-plane shear capacity of load-bearing walls is of great importance in the seismic design of structures. This study focuses on the shear behaviour of wide-spaced reinforced partially grouted (WRPG) concrete masonry walls. Twenty one shear walls were constructed with reduced-scale concrete masonry units. The experimental program consisted of eight groups of tests, with two or three identical specimens in each group. The specimens were subjected to monotonic lateral load, under near pure-shear boundary conditions. The parameters of the study include methods of load application, boundary conditions, aspect ratio, initial axial stress and specimen size. The shear capacities of the walls were compared against the predicted shear from four empirical equations. The sensitivity of the initial stiffness and different methods for calculation of ductility are discussed in detail. Lastly, the idea of strut-and-tie modeling was investigated for WRPG walls.