This report documents the computer program FUNWAVE based on the fully nonlinear Boussinesq model of Wei et al. (1995). The documentation provides a description of the governing equations and the numerical scheme used to solve it. A user's manual is provided and gives instructions on how to use various preprocessors and postprocessors to set up and read data files needed for model runs. Fortran code is provided for one and two-dimensional versions of the model, as well as for the additional data processing programs. Finally, several example calculations are documented.