Hazrat Muawiz (ra) belonged to the Khazraj tribe of the Ansar. Hazrat Muawiz’s (ra) father’s name was Harith bin Rifa‘ah. His mother’s name was Afraa bint Ubaid. Hazrat Muaz (ra) and Hazrat Auf (ra) were his brothers. All three of these brothers used to be referred to by the name of their father as well as their mother. Hence, all three were also known as Banu Afraa [the sons of Afraa].
(Ali Ibn al-Athir, Usd al-Ghabah fi Ma‘rifat al-Sahabah, Vol. 5, Muawiz bin Afra [Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 2003] 231) (Ibn Saad, Al-Tabaqat al-Kubra, Vol. 3, Muawiz bin Afra (Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 1990), 374.)