Unequal treaty is the name given by the Chinese to a series of treaties signed during the 19th and early 20th centuries, between China (mostly referring to the Qing dynasty) and various Western powers (specifically the British Empire, France, the German Empire, the United States, and the Russian Empire), and the Empire of Japan. The agreements, often reached after a military defeat or a threat of military invasion, contained one-sided terms, requiring China to cede land, pay reparations, open treaty ports, give up tariff autonomy, legalise opium import, and grant extraterritorial privileges to foreign citizens.

With the rise of Chinese nationalism and anti-imperialism in the 1920s, both the Kuomintang and the Chinese Communist Party used the concept to characterize the Chinese experience of losing sovereignty between roughly 1840 to 1950. The term "unequal treaty" became associated with the concept of China's "century of humiliation", especially the concessions to foreign powers and the loss of tariff autonomy through treaty ports.

Japanese and Koreans also use the term to refer to several treaties that resulted in the loss of their sovereignty, to varying degrees.