The harmonic electroelastic vibrations of a thin ring plate are considered. The effect of boundary conditions on the natural frequencies is studied. The asymptotic properties of the frequency spectrum are determined. The dependence of the resonant and antiresonant frequencies and the dynamic electromechanical-coupling coefficient on the relative size of plate is analyzed Keywords: piezoceramic plate, resonant and antiresonant frequencies, asymptotics of frequency spectrum Introduction. Piezoelectric circular thin-walled elements are used in various ultrasonic devices. The axisymmetric radial vibrations of thin piezoceramic disks and ring plates with thickness polarization were studied in many publications [1,4,5,7,8,10,11,13,14] beginning with [12]. However, no systematic analysis of the influence of the boundary conditions on the resonant frequencies has been performed. This issue is discussed in the present paper.We will establish the asymptotic properties of the frequency spectrum and will show that they can be determined with an admissible error by simple asymptotic formulas even at low frequencies. We will also ascertain which boundary conditions correspond to a more rigid mechanical system. The dependence of the resonant and antiresonant frequencies and the dynamic electromechanical-coupling coefficient (EMCC) on the relative size of the plate will be analyzed.1. Problem Formulation. Consider a thin piezoceramic plate of thickness h. We choose a cylindrical coordinate system Or z q with the plane z = 0 coinciding with the midsurface of the plate. If the plate has thickness polarization and undergoes