Reactive power compensation in radial distribution systems (RDS) is an important requirement for improving the system power quality and security. Grey wolf optimization (GWO) technique is a modern technique based on updating the positions of populations around the best solutions. Grey Wolf Optimizer (GWO) inspired by grey wolves (Canis lupus). The GWO algorithm mimics the leadership hierarchy and hunting mechanism of grey wolves in nature. Four types of grey wolves such as alpha, beta, delta, and omega are employed for simulating the leadership hierarchy. In addition, the three main steps of hunting, searching for prey, encircling prey, and attacking prey, are implemented. This work presented and applied for determine the optimal locations and sizes of Distribution Static Synchronous Compensator (DSTATCOM) in RDS as a reactive power source. The considered objective function is a multi-objective function which includes minimizing the real power losses, enhancing the voltage profile and improving the system stability, concurrently. To show the efficiency of the proposed technique it is applied on the stranded IEEE85-bus system and the captured results are compared to the founded results of the basic SCA techniques. The simulation reveals to that the proposed algorithm is more superior compared to the other reported algorithms.