Rift Valley fever (RVF) is a zoonotic arthropod-borne viral disease of immense economic importance, especially in sub-Saharan Africa. It is caused by the RVF virus (RVFV), a member of the genus Phlebovirus and family Phenuiviridae. The virion is enveloped, with a tripartite single-stranded RNA genome comprising the Large (L), Medium (M) and Small (S) segments of negative or ambisense polarity. Apart from humans, many domestic and wild animals can be affected, including cattle, sheep, goats, donkeys, camels, buffaloes, elephants and antelopes. Transmission of RVFV occurs through bites of infected mosquitoes, contact with infected animal tissues, bodily fluids and fomites, or vertically. The types and severity of clinical signs depend on the age and species of the infected host. RVF has the potential to emerge in a new location and/or reemerge after some period of absence of outbreaks. Re-emergence occurs via any of two modes: renewed replication and transmission of RVFV already existing in the environment or through fresh reintroduction of the virus into the environment. RVF outbreaks can be devastating, resulting in high numbers of human infections, hospitalisations and deaths, and also abortions, foetal malformations and massive mortalities in animals, and ultimately becoming a public health concern with resultant huge economic losses. Although RVF vaccines are used in animals, no vaccine or drug has been approved for human treatment. This chapter highlights the epidemiology of RVF among humans, animals and vectors in Africa.