Purpose <p>This article aims to determine the critical buckling temperature and thermomechanical free vibration response of a porous functionally graded material (FGM) nanoplate sandwiched between porous magneto-electro-elastic (MEE) plate layers, taking into account temperature-dependent material properties.</p> Methods <p>The upper surface of the FGM host structure is considered zirconia (ZrO ), and the lower surface is stainless steel (SUS304). In addition, the MEE face layers are considered to be homogenous volumetric mixtures of cobalt-ferrite (CoFe O ) and barium-titanate (BaTiO ). It is assumed that the host structure’s effective mechanical and thermal material properties are graded in the thickness direction according to the power law distribution. The effective mechanical, electrical, thermal, and magnetic properties of the face plates are obtained by the rule of mixture. This study was conducted using sinusoidal higher-order shear deformation theory (SHSDT) and nonlocal strain gradient elasticity theory (NSGT). Hamilton's theory is utilized to derive the equations of motion of sandwich nanoplates. Closed-form solutions are obtained by the use of Navier's method.</p> Results <p>Parametric simulations are carried out to examine the effects of the power law index, nonlocal parameters, electric, magnetic, and thermal loads, porosity volume fraction, porosity distribution and volume ratio of CoFe O and BaTiO on the free vibration and buckling behavior of the nanoplate. The results of the simulations are compared with published works to verify the accuracy of the proposed method.</p> Conclusion <p>According to the analysis results, it is determined that the power law index, porosity ratio, porosity distribution function, temperature dependent properties, magneto-electro-thermo-mechanical loads and nonlocal factors significantly affect the thermomechanical behavior of the nanoplate.</p>