Ankle-Foot Orthoses (AFOs) are a promising solution for replacing crutches and enabling walking in various medical conditions that require offloading of the foot or ankle. Recently, we studied the effects of three types of unloading devices – forearm crutches, knee crutch, and prefabricated AFO on various gait parameters (Eshraq et al., 2024). The AFO has shown favorable performance over the other devices, but several substantial limitations were found. Therefore, this study aims to develop and evaluate a novel adjustable-loading AFO. Our AFO introduces several innovative components to address the limitations found in existing AFOs. First, a patient-specific shank brace is designed based on a 3D scan to distribute loads across the shank’s soft tissues more effectively and enhance comfort. Second, an adjustable load mechanism is introduced to allow precise distribution of the loads between the shank and the plantar foot by adjusting the brace height. Finally, customized contact plates support the foot medially and laterally, featuring a Roll-Over Shape (ROS) fitted using experimental gait data. The ROS is computed by transforming the foot center of pressure into a shank-fixed coordinates system and is aimed at providing a natural and symmetric gait despite the offloading and lack of ankle flexion in the affected leg. Subsequently, topology optimization is employed to minimize the orthosis weight. The expected benefits of using our orthosis are to mitigate adverse effects caused by immobilization of the proximal leg, and to enhance recovery by accurately adjusting the partial loading. Its performance will be evaluated through biomechanical analysis, including GRF, pressure distribution, kinematics and kinetics parameters, metabolic cost, and subjective user experience.