The technological advancements in weapons and weapon systems continues to increase, and with these advancements the risk in safety increases as well. These weapons pose a great threat to naval task forces. In order to carry out missions safely, the task forces need to be equipped with defensive weapon systems. In this thesis the focus lies on air defense weapon systems. Originally, the selection of air defense weapon systems is done for a singular vessel, not taking into account the influence the other vessels in the task force may have on the operational effectiveness of the weapon systems in a group setting. This report presents an investigation into the selection and distribution process of weapon systems across a task force, while balancing the effectiveness and the costs of the weapon systems. The developed model utilizes a Weapon-Target-Allocation model in combination with the NSGA-II algorithm to generate the selection and distribution of weapon systems across the task force.