East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the region is recognized in the United Nations Statistics Division scheme as encompassing 18 sovereign states and 4 territories. It includes the Horn of Africa to the North and Southeastern Africa to the south.

In a narrow sense, particularly in English-speaking contexts, East Africa refers to the area comprising Kenya, Tanzania, and Uganda, largely due to their shared history under the Omani Empire and as parts of the British East Africa Protectorate and German East Africa. Further extending East Africa's definition, the Horn of Africa—comprising Djibouti, Eritrea, Ethiopia, and Somalia—stands out as a distinct geopolitical entity within East Africa.

The East African Community, an economic and political bloc, currently includes the Democratic Republic of the Congo, Somalia, Burundi, Kenya, Rwanda, South Sudan, Uganda and Tanzania. Notably, the African Great Lakes region overlaps significantly with these countries.

Inside of Somalia there are two unrecognised states; Somaliland and Puntland, although Puntland still wants to join back with Somalia, for now it is independent. Adjacent to these mainland territories are island nations and territories such as the Comoros, Mauritius, Seychelles, Réunion, Mayotte, and the Scattered Islands in the Indian Ocean.

Regions including portions of Mozambique and Madagascar, often aligned with Southern Africa, share significant historical and cultural connections with East Africa, particularly through the Indian Ocean's maritime networks. Sudan is also sometimes included due in part because it is a member of the Common Market for Eastern and Southern Africa (COMESA) free trade area.

According to the theory of the recent African origin of modern humans, the predominantly held belief among most archaeologists, East Africa in the area of the African Great Lakes is where anatomically modern humans first appeared. There are differing theories on whether there was a single exodus or several; a multiple dispersal model involves the Southern Dispersal theory. Some researchers have suggested that North Africa was the region of Africa from which modern humans who first trekked out of the continent.

According to both genetic and fossil evidence, it has been posited that archaic Homo sapiens evolved into anatomically modern humans in the Horn of Africa around 200,000 years ago and dispersed from there. The recognition of Homo sapiens idaltu and Omo Kibish as anatomically modern humans would justify the description of contemporary humans with the subspecies name Homo sapiens sapiens. Because of their early dating and unique physical characteristics idaltu and kibish represent the immediate ancestors of anatomically modern humans as suggested by the Out-of-Africa theory.

In 2017 finds of modern human remains, dating to ca 300,000 years ago in Jebel Irhoud in Morocco, suggested that modern humans arose earlier and possibly in a larger area of Africa than previously thought.