Ala al-Din Tekish (Persian: علاء الدين تكش; full name: Ala ad-Dunya wa ad-Din Abul Muzaffar Tekish ibn Il-Arslan) or Tekesh or Takesh was the Shah of Khwarazmian Empire from 1172 to 1200. He was the son of Il-Arslan. His rule was contested by his brother, Sultan Shah, who held a principality in Khorasan. Tekish inherited Sultan Shah's state after he died in 1193. In Turkic, the name Tekish means he who strikes in battle.^[2]

In 1194, Tekish defeated the Seljuk sultan of Hamadan, Toghrul III, in an alliance with Caliph Al-Nasir, and conquered his territories. After the war, he broke with the Caliphate and was on the brink of a war with it until the Caliph accepted him as Sultan of Iran, Khorasan, and Turkestan in 1198.

He died of a peritonsillar abscess in 1200^[3] and was succeeded by his son, Ala ad-Din Muhammad.