The electromechanical transduction properties of any dielectric elastomer are intrinsically regulated by the dielectric permittivity of the material. This parameter proportionally controls both the achievable active stresses and strains. Accordingly, a suitable increase of the material permittivity may provide a valuable means to improve the performance of a dielectric elastomer actuator. This chapter provides a brief overview of the most used methods, mainly based on purely physical approaches, currently available for increasing the dielectric permittivity of rubber-like insulators.