Cretaceous transgressions left marine deposits over wide areas of Tethys, from which it is possible to develop paleogeographic maps depicting the configuration and extent of marine and continental paleoenvironments, including oceanic seafloor and structural patterns. Such maps can be used for testing the evolution of continent—ocean interactions and their climatic implications to increase understanding of the sedimentary products and processes related to them during the Cretaceous. The objectives of this chapter are to investigate the Cretaceous paleogeographic changes at stage or substage level when necessary, focusing on some key periods during which major changes occurred.