Nonlinear oscillations of dielectric elastomers are widely used in the application of dielectric devices. However, the effects of the dielectric permittivity on the oscillations have been overlooked previously. In this article, an analytical model is proposed to study the nonlinear oscillations of dielectric elastomer actuators. The motion equation is obtained by using Hamilton’s principle. Numerical results of the model show that the stretch-dependent dielectric permittivity can change the thickness of the deformed film by about 65% near the resonance frequency. It is anticipated that this work can provide a new way to adjust the nonlinear oscillations and design more robust DE actuators.