Masaaba , also known as Bagisu, Gisu, Kisu, Lugisu, Lumasaaba or Masaba, is a language of Uganda.

It has over 1,650,000 users in Bududa, Bukedea, Bulambuli, Kapchorwa, Kween, Manafwa, Mbale, and Sironko districts; Mount Elgon area.

Dialects of Masaaba include; Ludadiri (Dadiri), Lubuuya (Buuya, Buya), Luwalasi, Luyobo, Luteza, Lufumbo. Intelligibility of Dadiri and Buuya 83%. Central and Southern varieties of Buuya 93%. Lexical similarity with Saamia, Isukha and Logooli.

Ludadiri is the main Northern variety; Lubuuya is the main Central or Southern variety. Orthography guide published but inadequate for dialectal variants. It is also taught in primary schools.