A finite element model based on continuum shell elements available in ABAQUS software has been developed for the free vibration analysis of FGM sandwich panels. Applications to sandwich plates with different combinations of FGM core and/or FGM face sheets satisfying through-the-thickness material gradations in the form of either power (P-FGM) or sigmoid (S-FGM) or exponential (E-FGM) distributions are considered. A user-defined material subroutine UMAT was used to implement functionally graded properties of the constitutive FGM layer. Numerical studies are given for free vibrations of sandwich plates subjected to different boundary conditions and with different structural parameters such as span to thickness, face sheet–core–face sheet thickness and aspect ratios, and volume fraction exponent. The studies showed very good agreement between the present results and those existing in the literature that confirmed the accuracy of the developed model. A series of numerical solutions obtained in the research extends the results of testing examples and may serve as additional benchmark data for other researchers.