In-plane behaviour of reinforced concrete masonry walls (RCMW) is complex, as the shear resisting mechanism is influenced by the characteristics of concrete masonry assemblage, steel reinforcement (vertical and horizontal), and internal grouting used. Rational design guidelines are given in the masonry design standards to determine the in-plane capacities of RCMWs. However, the structural reliability of design guidelines provided in the standards, particularly in the Australian masonry standards (AS 3700, 2018) is not well examined. Therefore, the reliability of in-plane shear design provisions of AS 3700 (2018) has been evaluated in this study. An experimental database of RCMWs was developed for this purpose; subsequently, First-Order reliability method was used to verify the reliability of in-plane shear design. The reliability analysis revealed that the existing design provisions in AS 3700 (2018) are marginally failing to satisfy the target reliability index of 4.0 set in this study, however further sensitivity analyses are needed to verify appropriate capacity reduction factor for the design.