Weight reduction of Unmanned Aerial Vehicle (UAV) components and systems is one of the most essential factors for aviation. Take-off gross weight can be divided into crew weight, payload, fuel, and empty weight. The empty weight is divided into the structure, engine/s, landing gear, avionics and fixed equipment. Engine/s, landing gear, avionics and fixed equipment are selective items. Weight optimization can be made for structure and landing gear to minimize aircraft total weight. The main objective of the present study is to optimize weight and reach safe landing for a medium range UAV landing gear. The reduced weight can be used to increase payload and/or fuel to increase range or endurance of the UAV. In the present study, ANSYS shape (Topology) optimization tool is used to get a proposed shape for the UAV landing gear. Then parametric size optimization of the shape proposed was done. Design of experiment (DOE) technique is used in order to get the minimum weight for the landing gear at a specified stress limit. Aluminum alloy 7075-T61 and bi-directional carbon fiber which are the most common used materials in UAVs landing gear were used, It was found that using topology weight optimization technique reduces Aluminum Alloy landing gear weight by (30.4 %) changing the material to be bi-directional carbon fiber without optimization reduce landing gear weight with additional value (27.9 %). Optimizing bi-directional carbon fiber landing gear reduces the weight with additional value (4 %) to be the total weight ratio by (62.3 %). The optimization technique for weight optimization is a guide to optimize any other type of landing / part to minimize the total weight for the Unmanned Aerial Vehicle.