The Aksu River (Uyghur: ئاقسۇ دەرياسى, romanized: Aqsu deryasi; simplified Chinese: 阿克苏河; traditional Chinese: 阿克蘇河; pinyin: Ākèsū Hé; means "white/clear water" in Uyghur and Kyrgyz languages) is a transboundary river in the Xinjiang province in China and Ak-Suu District of Issyk-Kul Province of Kyrgyzstan.

The middle section, between the Kyrgyz-Chinese border and the confluence with the Toshkan, is called Kumarik River (Chinese: 库玛拉克河, Kyrgyz: Сарыжаз).

The river takes its roots at the Semyonov glacier in the Central Tian Shan mountains of Kyrgyzstan, close to the tripoint with Kazakhstan and China.

[2] From here it first runs towards the west, before turning south and breaking through the high mountains and into Xinjiang in the northern parts of the Tarim Basin.

At the city of Aksu it meets its main tributary, the Toshkan (Kakshaal), which flows in from the west.