Power distribution utilities are striving to optimize operations and improve grid reliability to meet the demands and expectations of their customers. These goals can be further achieved by optimally unlocking the potential of Volt/VArdevices and distributed generations considering reliability en-hancement perspectives. This paper proposes a novel Volt/VAR regulation-oriented reliability assessment framework for dis-tribution systems, including inverter-based distributed energy resources (DERs) and online tap changers. The framework is developed based on a Mixed-Integer Linear Program (MILP) optimization method using a detailed linear AC optimal power flow (AC-OPF), leading to the best possible solution and enhanced computation time. For the first time, this study captures the impact of Volt/VArregulation in improving distribution system reliability, which is demonstrated through the improvements in the reliability indices, such as Average Interruption Duration Index (SAIDI) and System Average Interruption Frequency Index (SAIFI), after implementing Volt/VArregulation. Different case studies are verified on the IEEE 33- bus test system.