<p>In this article, the thermomechanical wave propagation analysis of sandwich nanocomposite plates with a triply-periodic-minimal-surface (TPMS) core layer and magneto-electro-elastic (MEE) surface layers are evaluated using the high-order shear deformation theory (HSDT). MEE surface plates are composed of a mixture of cobalt ferrite (CoFe₂O₄) and barium titanate (BaTiO₃) according to the rule of mixture, while the TPMS core layer is SUS304. Three different TPMS cells are considered for the core layer: Gyroid (G), Primitive (P), and Wrapped package-graph (IWP). It is assumed that the material properties of both MEE and TPMS plate structures exhibit temperature-dependent variations. The equations of motion for the sandwich structure are established using HSDT and nonlocal strain gradient elasticity theory (NSGT), while the wave equations are obtained through analytical solutions. The study explores the effect of nonlocal parameters, wave number, TPMS cell pattern, CoFe₂O₄ and BaTiO₃ mixture ratio, temperature increase, and thermal and electrical load parameters on the phase velocity and wave frequency of the sandwich plate. Based on the results, it is concluded that the parameters which are addressed significantly affect the wave propagation phase velocity and frequency of the sandwich plate, and that sandwich plates can be modeled to adapt to variable environmental conditions and tune the desired properties with appropriate parameter selection. It is aimed that this study will contribute to advanced aerospace studies where the effect of temperature change is significant, and where both lightweight and high strength and energy absorption capabilities are prominent.</p>