We present a Green’s function theory of the nonlinear interaction of surface polaritons propagating along the plane interface between vacuum and a noncentrosymmetric dielectric medium. These nonlinear effects are induced by the nonlinear polarization of the dielectric medium. The nonlinear effects considered are second harmonic generation of a surface polariton, the nonlinear mixing of two surface polaritons, and optical rectification of a surface polariton. Numerical estimates for the magnitudes of these effects are presented for GaAs, for which the necessary second‐order susceptibilities in the infrared have been determined.