The Tongmenghui (同盟會 Pinyin: Tóng Méng Huì, literal meaning: "United Allegiance Society"), also known as the United League or the Revolutionary Alliance, was organized by Sun Yat-sen and Sung Chiao-jen in Tokyo, Japan on August 20, 1905.

The new body was created through the unification of Sun's Xingzhonghui (Revive China Society), the Guangfuhui (Restoration Society) and other Chinese revolutionary groups.

Combining republican, nationalist, and social objectives, the Tongmenghui's political platform was "to overthrow the Manchu barbarians, to restore China to the Chinese, to establish a republic, and to distribute land equally."

Among the Allegiance's members was Wang Jingwei, leader of the Japanese puppet state in China during WWII.

After the establishment of the Republic of China, the Tongmenghui formed, in August 1912, the nucleus of Sun's new Kuomintang (Nationalist Party).

See also: History of the Republic of China