The changes in the thickness‐shear resonance frequencies of circular crystal plates subjected to steady in‐plane acceleration of arbitrary direction are studied. A closed‐form solution for a circular plate under acceleration with three or more points of mounting is obtained. From this solution, initial stress and strain fields are computed at each and every point of the plate as a function of plate orientation, direction of acceleration, and positions of supports. These fields are then taken into account in the coupled equations of the incremental thickness‐shear and flexural vibrations through the second‐ and third‐order elastic stiffness coefficients of the crystal. Due to the space dependence or nonuniformity of the initial fields and the smallness of the frequency changes, (Δf/foin order of 10−9) a perturbation method is used to calculate the changes in the thickness‐shear resonances. The frequency changes as function of the acceleration direction for several configurations of the supports forATcut of quartz are computed. These are then compared with experimental values of A. W. Werner [Interim Reps. 10−11, Bell Telephone Labs. (1959)] and W. L. Smith [Interim Reps. 12−13, Bell Telephone Labs. (1960)].