The Battle of Qatwan (Chinese: 卡特萬之戰) was fought in September 1141 between the Qara Khitai (Western Liao dynasty) and the Seljuk Empire and its vassal-state the Kara-Khanid Khanate.

In 1142, Yelü sent Erbuz to Khwarazm to pillage the province, which forced Atsiz to agree to pay 30,000 dinars annual tribute.

[12] Accounts of the battle are given in a number of sources, for example in Sadr al-Din al-Husayni's Arabic chronicle of the Seljuks.

Abu'l Fadl, however, remained with the soldier who played the role of the Sultan until the end of the battle, and was soon captured.

Turkan-Khatun was released for ransom of 500 thousand dinars, Emir Kumach and his son – for 100 thousand dinars, and Abu'l-Fadl was freed without ransom when Yelü Dashi learned that the sons of the ruler of Segestan had seized their father's possessions.

After the defeat, Sanjar intended to go to Balkh, and his path lay close to the enemy's location, “since it was impossible to go by other roads.” However, Yelü Dashi ordered not to intervene; Al-Husayni attributes the following words to the Kara-Khitan ruler: “To close the path for the one who retreats means to force him into a desperate battle.