Banu Abdul Qays

Banu Abdul Qays (Arabic: بنوعبدالقيس‎‎)
Banu Rabi'ah, Adnanite
A family tree depicting the ancestry of the Banu Abdul Qays.
Location	Eastern Arabia
Descended from	Abdul Qays ibn Qurayy ibn Afsa
Religion	Christianity, later Islam

The Banu Abdul Qays (Arabic: بنوعبدالقيس‎‎) is an ancient Arabian tribe from the Rabi`ah branch of the "North Arabian" tribes. In pre-Islamic times, the Abd al-Qays frequently raided Iran. When he became of age, Shapur II made it his first order of business to punish the Abd al-Qays. He led an army across the Persian Gulf and devastated large parts of Eastern Arabia and Syria, slaughtering most of the Abd al-Qays on the way. Later in his reign, Shapur moved many Abd al-Qays people to Kerman Province in Iran.

During the Arab conquest of Iran, the Abd al-Qays migrated to Iran in large numbers and carried out extensive raids in southern Iran. Sizable groups of them settled down in Tavvaz near Dalaki in Bushehr Province. In the early 8th century, 4,000 Abd al-Qays warriors accompanied Qotayba on his campaign into Khorasan in Iran.

The Abd al-Qays were one of the inhabitants of the coast of Eastern Arabia, including Bahrain island. There are many gaps and inconsistencies in the genealogies of Abd al-Qays in Bahrain, thus Baharna are probably descendants of an ethnically mixed population. Bahraini society has traditionally divided itself into three genealogical categories in order: "ansab" (clear genealogies), "la ansab" (unclear genealogies) and "bani khudair" (foreigner). According to one author, Baharna were probably "la ansab" because they have unclear genealogies.

Abd al-Qays were mostly Christians before the advent of Islam.