Conductive polymer composites with the addition of conductive base particles, such as metal powders or carbon-based particles (such as carbon nanotubes, graphene, carbon black or carbon nanofibers), can change their insulating properties, allowing the flow of electric current. The behavior of conductive thermoplastics is extremely complex due to the numerous intrinsic multifunctional couplings such as thermal, electrical and mechanical interdependencies. The thermos-electro-mechanical response of a conductive device at the macroscopic level is dependent on the geometry and boundary conditions, including zones that exhibit stress or current concentrations, or zones with high/low exposure to convection. From a microscopic viewpoint, the material behavior is governed by the nature and distribution of the composite phases (e.g., polymeric matrix and conductive particles) as well as the formation and distribution of micro-voids. Therefore, in order to understand the response of 3D printed conductive devices, the thermos-electric-mechanical response of these composites must be studied at the microscopic level. The analysis of the conductive thermoplastic filament would isolate the behavior of the material by discarding the structural effects. So far, most research efforts have focused on the thermo-electro-mechanical response of printed samples, which adds strong structural effects due to the additive manufacturing process. Nevertheless, there is no work addressing the thermal, electrical and mechanical responses of conductive filaments in a coupled fashion, taking into account the different interplays that occur between those physics. In this work, Javier Crespo-Miguel et al. from the Department of Continuum Mechanics and Structural Analysis, Universidad Carlos III de Madrid, developed an experimental method to characterize conductive filaments from a combined mechanical, electrical and thermal perspective. To overcome experimental limitations that prevent a complete microstructural analysis of the problem, the authors developed a full-field homogenization framework that considers all interactions observed in conductive thermoplastics, such as viscoplasticity, electrical, thermal conduction, convection and heat generation via Joule effect, as well as for the interdependences between them. The framework captures the macroscopic responses observed in the experiment by considering the periodic Representative Volume Element of the microstructure. After experimental validation, the framework was proved as a valuable tool that can be applied to optimize fabrication requirements to obtain the desired properties in the final product, i.e., stiffer products, filaments with higher thermal conductivity or better sensing capabilities.