Transtibial prosthetic devices or below-knee prosthetic devices are used as assistive devices in replacing the part of the leg below the knee joint in case of amputation. The different builds in amputees require the need for the accessibility to custom-made lucrative prosthetic devices in order to reintegrate the amputees into society. The goal of this study is to design a personalized transtibial prosthetic device that closely mimics the human gait by the use of topology optimization. Additive manufacturing is used to reduce the fabrication time of a traditional transtibial prosthetic device. The creation of the transtibial prosthetic device model is through computer-aided drawing (CAD) and afterwards simulated using ANSYS for the comparison and contrasting of the optimized design. The materials used in the design of the transtibial prosthetic device are polypropylene and titanium alloy. Simulation works reveal that there is a 12.8 reduction in the minimum equivalent (von-Mises) stress and a 51.29 reduction in the minimum equivalent elastic strain of the benchmark socket, and titanium alloy is the superior material in the fabrication of prosthetic foot as it greatly reduced the total deformation, equivalent (von-Mises) stress and equivalent elastic strain of the SACH foot as compared to polypropylene in the initial contact, midstance and the push-off phases of the gait cycle. Topology optimization of both the socket and foot models reduced the stiffness and density of material volume up to 60. Voronoi pattern developed on the socket and foot models mirrors the reduction done on material volume by topology optimization. © 2021 Institute of Physics Publishing. All rights reserved.