With a basin covering 1.4 million km2, the Zambezi is the fifth largest drainage basin in Africa. Bounded by the 9°S and 21°S parallels, it is home to approximately 30 million people and is officially shared by eight riparian countries. The river stretches over 2600 km across Southern Africa, from Angola in the west to Mozambique in the east, and plays a vital role in the region’s cultural identity and economy. Along the course of the Zambezi River and the main tributaries, a number of relevant features can be highlighted. These include some very large wetland areas and lakes, major dams, and UNESCO World Heritage Sites. A substantial hydropower potential of 13,000 MW, of which only about 5000 MW are currently exploited, coexists with ecologically rich areas, some among them listed as Ramsar Sites. In recent years, the study of the basin’s hydrology has gained relevance as it holds the key to answering concerns of future water availability, survival of riverine natural ecosystems, flood prevention, and the optimization of dam operations. In this chapter, a brief account of the basin is given. Emphasis is placed upon its main features, climate, runoff regime, hydrological studies conducted in the area and the main difficulties they face, and current concerns as well as future challenges related to water resources.