The use of reinforced concrete block masonry walls became moreattractive for designers in the past decade for many reasons. Such walls are eithersubjected to uniformly distributed or concentrated loads.In this study a numerical program was performed to investigate thebehaviour of the masonry walls by both the 2-D and 3-D finite element method.However, the 2-D finite element method was not capable of examining the effectof all design parameters and in order to achieve a better and accuraterepresentation for the walls,3-D finite element method was applied. The effectsof the type of loading, holes grouting, area of reinforcing steel, sides boundaryconditions and the load eccentricity on the developed deformations and stresseswas examined.The behaviour of reinforced masonry walls resting on either a rigid or anelastic foundation was studied. The effect of having an edge or a middle local gapof soil underneath the wall was also investigated. Two types of modeling wereexamined: while the wall panel was represented by quadratic elements in the 2-Danalysis and eight nodes hexahedral elements in the 3-D analysis, the type of soilwas represented either by Winkler model or by quadratic elements (semi-infinitehalf space). Fifty seven models were examined to study the effect of type of soiland loss of support on masonry wall having different sides boundary conditionsrepresenting intersecting connecting walls as exist in practice. Different sizes ofsoil gaps at different locations were also studied.An experimental program was performed to investigate the behaviour ofreinforced masonry walls resting on either a rigid or an elastic foundation takinginto consideration the different types of soil and different sizes of soil gaps atdifferent locations. Eighteen masonry wall panels were tested and the results werecompared to those obtained numerically. The comparison proved a reasonableaccuracy and similarity between the results.It was found that the 2-D finite element method is not accurate whendealing with concentrated loads. Special care should be taken when an eccentricload is applied since it causes high tensile and compressive stresses at the twowall faces. Changing the type of soil underneath the wall had a considerable effecton the developed vertical deformation. It was also observed that the end gap ismore serious than the middle gap since the corresponding increase in thedeformations and stresses is much higher.Many conclusions, relations and recommendations which may be useful fordesigners were obtained and introduced in the form of tables and curves.