Hydrological modeling in Malaysia using two-dimensional fully distributed and physically based model is relatively new. Basic guidelines in choosing model dimensions (i.e., 1D, 1D-2D, 2D, and 3D) are discussed. The application of 3D model will give more accurate results if the groundwater movement is considered but requires more time to simulate and prepare input data. However, the 1D model is less accurate in representing the real topography of the study area, even though requires short time to simulate. This chapter also gives an overview about the hydrological modeling in Malaysia which ranges from 1D to 3D. Several researches on hydrology using different model were reviewed. The success of each model will be highlighted.