<p>This study presents a novel investigation of geometrically nonlinear transient behaviour of a functionally graded porous skew (FGPS) plate under thermal loading, emphasizing the combined effects of porosity distributions and geometric non-uniformities. A notable contribution of this work is the incorporation of temperature-dependent material gradation by applying a modified power-law model, coupled with the analysis of void porosities characterized by geometrical skewness. An advanced computational approach is proposed to develop a nonlinear finite element formulation using improved first-order shear deformation theory (IFSDT), and the governing equations are systematically derived employing von Kármán-type nonlinear strain–displacement relations and Hamilton's principle. The Newmark time integration method is used to capture the transient thermal responses of the FGPS plate. The research presents a comprehensive analysis of the way in which thermal fields, porosity profiles, and skew angles interact to influence the dynamic behaviour of FGPS plates for different material gradation profiles. The findings highlight that the nonlinear transient responses of the FGPS plates are strongly influenced by porosity profiles and material gradation under varying thermal conditions, particularly in skewed plates as opposed to uniform plates, offering essential design guidelines for thermomechanical applications involving skewed porous structures.</p>