According to various aspects, exemplary embodiments are disclosed of thermal interface materials including electrically-conductive material, shields including thermal interface materials, and related methods. In an exemplary embodiment, a thermal interface material generally includes a top surface, a bottom surface, and one or more outer side surfaces extending between the top and bottom surfaces. Electrically-conductive material is along and/or adjacent the one or more outer side surfaces. The thermal interface material may be configured to be operable as a waveguide through which energy below a cutoff frequency cannot flow. The electrically-conductive material may be parallel with a direction of heat flow from a heat source to a heat removal/dissipation structure when the bottom surface is positioned against or adjacent the heat source and the top surface is positioned adjacent or against the heat removal/dissipation structure.