The Yem are an ethnic group living in south-western Ethiopia. They are also called by their neighbors as the Janjero, but the Yem consider this exonym derogatory, since it sounds similar to the Amharic word "zinjero" which means "baboon". Their native language is Yemsa, one of the Omotic languages, although many also speak Oromiffa or Amharic. The neighbors for Yem include the Gurage, Hadya and Kembata to the east across the Omo River and the Jimma Oromo to the south, north and west.
The first reference to Yem as a political unit is found, under the name of Jangero, in the victory song of King Yesaq (1412-1427) of the Christian kingdom of Ethiopia, as paying tribute in the form of horses to the king. The first European traveler to mention Yem was the European traveler Father Fernandez, who travelled through their homeland in 1614.
Their number was not definitely known until recently, as Aklilu Yilma states, "Bender gives the estimate as '1000' (Bender 1976: 4), whereas the Ethnologue reports the figure of '1000-4000' speakers of Yemsa (Grimes 1992:257). The report of the Central Statistical Office gives the 1984 census figures of the Yem people as 34,951 (Central Statistical Office 1991:61), but this census seems to comprise only the Fofa area." The 1994 national census reported 60,811 people identified themselves as Yem in the Southern Nations, Nationalities, and People's Region (SNNPR), of whom 59,581 lived in the around Fofa, and 52,292 speakers of the Yemsa language in the SNNPR, of whom 51,264 were living in the same area. The more recent 2007 national census reports that 160,447 were identified as Yem, of whom 84,607 lived in the Oromia Region and 74,906 in the SNNPR.