The aspiration of the present research paper is to present analysis of stresses distribution and displacement in a circular disc under the effect of rotation and of transversely isotropic piezoelectric functionally graded material with variable thickness. The stress components have been deduced analytically by using transition theory. The various components of stress are derived for the disc under rotation by applying the transition theory developed by Seth. Electrical displacement and mechanical stress equations are calculated using the stress–strain relationship. By inserting the obtained relation into the equilibrium equation, the unequal differential equation is derived. With the increasing value of thickness parameter, the radial stress changes in the intermediate surface of the rotating disk. Results have been discussed numerically and depicted graphically.