Ordu is a port city on the Black Sea coast of Turkey, and the capital of Ordu Province. Estimated population c. 2014: 195,817.

Ordu-Baliq (meaning "city of the court", "city of the army"), also known as Mubalik and Karabalghasun, was the capital of the first Uyghur Khaganate, built on the site of the former Göktürk imperial capital, 27 km north-to-northeast of the later Mongol capital, Karakorum. Its ruins are known as Kharbalgas in Mongolian, that is, "black city". They form part of the World Heritage Site Orkhon Valley Cultural Landscape.