<p>This work presents a computational model for magnetomechanical vibration analysis of sandwich plates incorporating a fluid-saturated functionally graded porous core and arbitrarily oriented functionally graded material (FGM) stiffeners. The formulation combines Biot’s theory for fluid-saturated porous materials with a four variable higher-order shear deformation model (HSDT4), the pb2-Ritz method, and Lekhnitskii’s smeared stiffener technique. A unified description is established for plates subjected to magnetic fields and reinforced by such stiffeners, a configuration that has received limited attention in previous studies. The considered smart sandwich plate (SWFGPS) consists of three layers: a porous functionally graded magnetoelastic (PoFGMag) top face sheet, a saturated functionally graded porous (SFGP) core, and a stiffened FGM bottom face sheet. Material variations through the thickness follow a modified power law relation, with distinct porosity patterns assigned to the PoFGMag layer and the core. The magnetic field in the PoFGMag layer is represented by a combined cosine and linear distribution. Model accuracy and convergence are assessed through comparisons with available reference solutions. Parametric studies quantify the effects of material parameters, geometric ratios, the Skempton coefficient, the applied magnetic field, and stiffener configurations on vibration frequencies. The results clarify the coupled influence of magnetic effects, the fluid-saturated porous core, and the arbitrarily oriented stiffener system on sandwich plate responses and provide reference data for the analysis and design of smart sandwich structures.</p>