Most of the Gbe peoples have come from the east to their present dwelling-places in several migrations between the tenth and the fifteenth century. Some of the Phla-Pherá peoples however are thought to be the original inhabitants of the area who have intermingled with the Gbe immigrants, and the Gen people probably are immigrants from the north of Ga or Fante origin. In the late eighteenth century, many speakers of Gbe were enslaved and transported to the New World, causing Gbe languages to play a role in the genesis of several Caribbean creole languages.

Around 1840, German missionaries started linguistic research into the Gbe languages. In the first half of the twentieth century, the Africanist Diedrich Hermann Westermann was one of the most prolific contributors to the study of Gbe. The first internal classification of the Gbe languages was published in 1988 by H.B. Capo, followed by a comparative phonology in 1991. The Gbe languages are tonal, isolating languages and the basic word order is Subject Verb Object.

The Gbe language area is bordered to the west and east by the Volta River in Ghana and the Weme river in Nigeria. The northern border is between 6 and 8 degrees latitude and the southern border is the Atlantic coast. The area is neighbored mainly by other Kwa languages, except for the east and north-east, where Yorùbá is spoken. To the west, Ga-Dangme, Guang and Akan are spoken. To the north, it is bordered by Adele, Aguna, Akpafu, Lolobi, and Yorùbá.

Estimates of the total number of speakers of Gbe languages vary considerably. Capo (1988) gives a modest estimate of four million, while SIL's Ethnologue (15th edition, 2005) gives eight million. The most widely spoken Gbe languages are Ewe (Ghana and Togo) and Fon (Benin, eastern Togo) at three million and 1.7 million speakers, respectively. Ewe is a language of formal education for secondary schools and universities in Ghana, and is also used in non-formal education in Togo. In Benin, Aja (740,000 speakers) and Fon were two of the six national languages selected by the government for adult education in 1992.

Greenberg, following Westermann (1952), placed the Gbe languages in the Kwa family of the Niger-Congo languages. The definition of the Kwa branch has changed through the years, and Roger Blench classifies the Gbe languages have always been considered part of it and are currently classified as follows:

Gbe is a dialect continuum. Based on comparative research, Capo (1988) divides it into five clusters, with each cluster consisting of several mutually intelligible dialects. The borders between the clusters are not always distinct. The five clusters are:

The dialect continuum as a whole was called 'Ewe' by Westermann, the most influential writer on the cluster, who used the term 'Standard Ewe' to refer to the written form of the language. Other writers have called the Gbe languages as a whole 'Aja', after the name of the local language of the Aja-Tado area in Benin. However, use of this single language's name for the language cluster as a whole was not only not acceptable to all speakers but also rather confusing. Since the establishment of a working group at the West African Languages Congress at Cotonou in 1980, H. B. Capo's name suggestion has been generally accepted: 'Gbe' , which is the word for 'language/dialect' in each of the languages.

Ketu, a Yoruba settlement in present day Benin Republic (formerly known as Dahomey), might be an appropriate starting point for a brief history of the Gbe-speaking peoples. Ewe traditions refer to Ketu as Amedzofe ("origin of humanity") or Mawufe ("home of the Supreme Being"). It is believed that the inhabitants of Ketu originally belonged to the Yoruba Oyo people of Nigeria and were pressed westward by a series of wars between the tenth and the thirteenth century. In Ketu, the ancestors of the Gbe-speaking peoples separated themselves from other refugees and began to establish their own identity.

Yoruba attacks between the thirteenth and the fifteenth century drove a large section of the group still further westward. They settled in the ancient kingdom of Tado (also Stado or Stádó) on the Mono river (in present-day Togo). The Tado kingdom was an important state in West Africa up to the late fifteenth century.

In the course of the thirteenth or fourteenth century, the Notsie (or Notsé, Notsye, Wancé) kingdom was established by emigrants from the Tado kingdom; Notsie would later (around 1500) become the home of another group of migrants from Tado, the Ewe people. Around 1550, emigrants from Tado established the Allada (or Alada) kingdom, which became the center of the Fon people. Tado is also the origin of the Aja people; in fact, the name Aja-Tado (Adja-Tado) is frequently used to refer to their language.