The Abagusii (also known as Kisii (Mkisii/Wakisii) in Swahili, or Gusii in Ekegusii) are a highly diverse East African ethnic group and nation indigenous to Kisii (formerly Kisii District) and Nyamira counties of former Nyanza, as well as parts of Kericho and Bomet counties of the former Rift Valley province of Kenya

It is spoken natively by 2.2 million people (as of 2009), mostly among the Abagusii. Ekegusii has only two dialects: The Rogoro and Maate dialects. Phonologically they differ in the articulation of /t/. Most of the variations existing between the two dialects are lexical. The two dialects can refer to the same object or thing using different terms. Example Cat. While one dialect calls a cat ekemoni, the other calls it ekebusi. As well, the rogoro dialect calls sandals Chidiripasi while the maate dialect calls it chitaratara. Many more lexical differences manifest in the language. Maate Dialect is spoken in Tabaka and Bogirango. Most of the other regions use the Rogoro Dialect, which is also the standard dialect