AbstractDampers can be installed inside buildings to mitigate vibration and lateral displacement. Recently, a new type of tuned liquid wall damper (TLWD) was proposed, in which a reinforced concrete wall panel can contain various vertical openings, allowing internal water to flow to provide the damping effect. Generally, larger amounts of water lead to a better damping effect. However, this requires a larger opening area in the wall, which will reduce the strength of the wall. Therefore, a multiobjective optimization method, which considers both the strength and damping effects, was developed to accommodate the two conflicting design objectives in this work. The method starts with a local task (i.e., strength and damping). Once the individual objective is optimized, a global task accounts for all parameters. The optimal result is obtained by selecting the best solution from the global task. This approach achieves the optimal design of the TLWD system considering a wide range of size and number of the openings. It was concluded that, for optimal TLWD configuration, the panel has minor strength reduction while providing satisfactory damping capability for hazard mitigation. The method presented in this study can be used to design other types of structures with conflicting design objectives.