The development of improved power generation systems to support NASA's future deep-space exploration missions requires multi-faceted modeling to evaluate both the thermal-electric and thermal-mechanical performance of the thermal-electric generators (TEGs). To better determine generator characteristics that could meet mission needs, a fully-coupled thermal-electric-mechanical numerical model was developed in ANSYS Mechanical and ANSYS CFX via user-defined subroutines. All pertinent thermal-electric phenomena, namely the Joule, Peltier, Thomson and Bridgman heats, were coupled to the general heat transport equation via volumetric and surface source terms. The electric potential and current density were simultaneously solved for using the Electromagnetics Model within ANSYS CFX, and said quantities evolved implicitly with the solution, as to provide the necessary boundary conditions for Maxwell's equations. Thermal expansion was modeled using a Boussinesq approximation and was coupled to the heat and thermal-electric equations via the inherent geometric dependence of thermal-electric phenomena. Deformation based on thermal expansion was handled through an iterative re-meshing routine, and was investigated under free-floating, springloaded, and constrained system configurations. Said deformation was used to determine stresses generated within each component of the TEG via ANSYS Mechanical. All thermo-physical materials were treated as temperature-dependent. Insight into the thermal-electric and thermal-mechanical performance of a unicouple, with and without interfacial compliance materials, under the influence of thermal loading was gained.