Tsunami is a type of infrequent geohazards with devastating consequences, which makes accurate computer simulations of tsunami waves particularly desirable for hazard assessment and mitigation purposes. The evolution of a typical tsunami involves the generation, propagation and inundation phases. In this survey, we briefly describe the most common types of tsunamigenic sources and give a detailed review of some most widely used mathematical models for describing tsunami propagation. We emphasize the approximations adopted in each mathematical model and point out their most important advantages and disadvantages. Tsunami propagation modeling is computationally demanding, involving a wide span of spatial and temporal scales. While some of the approximate models are sufficiently accurate for describing wave behaviors at certain scales, they might not be applicable at other scales. Effective and efficient tsunami propagation simulations will likely depend upon the proper coupling of different models for different scales.