Abstract : Even though wave run-up is not a new subject, until recently analytical and numerical studies of long wave run-up on a plane beach have failed to identify the existence of resonant regimes. Furthermore, it was a common belief that the leading wave will result in the maximum run-up. Stefanakis et al. (2011) underlined the importance of resonant long wave interactions during run-up and run-down. In the current paper we provide additional results with the use of one-dimensional numerical simulations in the framework of the nonlinear shallow water equations with boundary forcing for plane and nontrivial beaches. Several wave profiles are used as forcing conditions to the boundary value problem. Resonant interactions between incident and receding waves are found to occur, depending on the beach slope and the wavelength, and result in enhanced run-up of non-leading waves.