Electric power utilities are paying a lot of attention right now to the optimal placement and sizing of distributed generation (DG) a at the radial distribution grids for the goal of minimizing real power loss. Power loss minimization has several built-in advantages, such as the feeder lines power flow will be reducing, relieving stress on feeder loading to extend their life, increasing the possibility of using the current facility to meet any increase in load demand, avoiding the need to buy power from the grid and saving money on loss compensating equipment, lowering customer bills, etc. In this paper, the optimal placement and size of distributed generation (DG) units will be addressed using one of the most popular metaheuristics optimization techniques namely the Grey Wolf Optimizer (GWO). The main aim of this paper is minimized the real power losses on distribution network and improved the voltage profiles and enhanced the voltage stability index by adding DG units on optimal location and determine the optimal sizing with satisfied the equality and inequality constrains. The approach proposed determining the optimal placement by reconfiguring the DG on all buses and calculating the real power losses. The optimal placement is achieved on a bus with the lowest real power losses. The optimal sizing of the DG unit can be achieved by using Grey Wolf Optimizer (GWO). GWO is a meta-heuristics optimization technique inspired by the social behavior of grey wolves. The IEEE 33 bus radial system will be tested to prove the superiority and efficiency of the proposed algorithm. According to the simulation results that were obtained and the evaluation of the various cases that were taken into consideration, the placement of DG units results in a large loss reduction with a favorable voltage profile as well as the line loading in the power distribution networks is released. © 2023 IEEE.