The tribe of Shammar (Arabic: شمّر Šammar) is a Qahtanite Arab tribe, descended from the ancient tribe of Tayy. It is one of the largest and most influential Arab tribes, with an estimated around 12 million members in the world: 3 million in Iraq, over 6.5 million in Saudi Arabia (concentrated in Ha'il), a Syrian population thought to exceed 0.5 million, and an unknown number in Jordan, Kuwait, and Qatar. The current seat of the tribe's leadership is in the city of Mosul in Northern Iraq. In its "golden age", around 1850, the tribe ruled much of central and northern Arabia from Riyadh to the frontiers of Syria and the vast area known as Al Jazira in Northern Iraq.
One of the early famous figures from the tribe was the legendary Hatim Al-Ta'i (Hatim of Tayy; died 578), a Christian Arab renowned for generosity and hospitality who figured in the Arabian Nights. The early Islamic historical sources report that his son, Adiyy ibn Hatim, whom they sometimes refer to as the "king" of Tayy, converted to Islam before Muhammad's death. Another figure from Tayy during this period was Zayd al-Khayr, a prominent member of Tayy who is said to have led Tayy's delegation to Muhammad accepting Islam.
The current leader of the Syrian Shammar is Sheikh Humaydi Daham al-Hadi, whose son Bandar al-Humaydi is military leader of al-Sanadid Forces.