Banu Yam (Arabic: بنو يام) are a large tribe native to Najran Province in Saudi Arabia, and are the principal tribe of that area. They belong to the Qahtanite branch of Arabian tribes, specifically the group known as Hamdan, and are therefore native to southwestern Arabia.
Their traditional way of life was well suited to life in the Arabian Desert and East Sahero-Arabian xeric shrublands they once lived in. Most have now moved in to small villages and given up their once nomadic way of life. The tribe of Yam was also the progenitor of two other important tribes: the Al Murrah and the 'Ujman of eastern Saudi Arabia and the Persian Gulf coast.
The Yam are notable among the tribes of Saudi Arabia for the vast majority of its members traditionally follow the small Isma'ili branch of Shi'ite Islam. Religious leadership is currently in the hands of the al-Makrami clan, who joined Yam through alliance some time in the 17th century. Members of the tribe can be found throughout Saudi Arabia due to migration, particularly the areas around Jeddah and Dammam. Unlike some other tribes of southwestern Saudi Arabia, Yam have traditionally had a large bedouin section, due to the proximity of their territories to the formidable desert known as the Empty Quarter.
They are also unlike some of their neighboring tribes in that they are recorded to have repeatedly raided the neighboring region of Najd, reaching as far north as Dhruma near Riyadh during the time of the First Saudi State in 1775, and causing much panic.