The potential of nonlinear conductivity spectroscopy for obtaining new information on the hopping dynamics of mobile charge carriers in disordered materials is analyzed from a theoretical as well as from an experimental point of view. The nonlinear conductivity spectra of simple hopping models are calculated by means of analytical methods and Monte Carlo simulations. It is shown that the nonlinearity of the high-frequency conductivity is strongly influenced by the local asymmetry of the potential landscape, while the nonlinearity of the low-frequency conductivity is sensitive to the structure of the long-range diffusion pathways. Furthermore, experimental results for the nonlinear conductivity of ion conducting glasses and polymers are reviewed.