The Banu Amir was a large and ancient Arab tribe originating from Western Arabia that dominated Najd for centuries after the rise of Islam. It is an Arab Adnanite tribe whose lineage traces back to Adnan and Ishmael, son of Abraham through Hawazin, and its original homeland was the border area between Nejd and Hejaz in Khurmah and Ranyah. Although the Banu Amir engaged in a long war with the Quraysh before the appearance of Islam —manifesting in particular as the Fijar War — the tribe gave a late allegiance to Muhammad and his immediate successors. The tribe produced several well-known Arabic poets, the most famous of whom was Labid ibn Rabi'ah, an author of one of the Seven Hanged Poems. Other poets included Amir ibn al-Tufayl, an important tribal chief; al-Ra'i al-Numayri, an opponent of Jarir; and the female poet Layla al-Akhyaliyyah. The protagonists of the romantic saga of Layla wal Majnun, Qays and Layla, also belonged to Banu Amir.

Najd is the central region of Saudi Arabia, in which about a third of the country's modern population resides. It is the home of the House of Saud, from which it pursued unification with Hejaz since the time of the Emirate of Diriyah.