Kunqu, also known as Kunju, Kun opera or Kunqu Opera, is one of the oldest extant forms of Chinese opera. It evolved from the Kunshan melody, and dominated Chinese theatre from the 16th to the 18th centuries.

Plays that continue to be famous today, including The Peony Pavilion and The Peach Blossom Fan, were originally written for the Kunqu stage. In addition, many classical Chinese novels and stories, such as Romance of the Three Kingdoms, Water Margin and Journey to the West were adapted very early into dramatic pieces.

Today, Kunqu is performed professionally in seven Mainland Chinese cities: Beijing (Northern Kunqu Theatre), Shanghai (Shanghai Kunqu Theatre), Suzhou (Suzhou Kunqu Theatre), Nanjing (Jiangsu Province Kunqu Theatre), Chenzhou (Hunan Kunqu Theatre), Yongjia County/Wenzhou (Yongjia Kunqu Theatre) and Hangzhou (Zhejiang Province Kunqu Theatre), as well as in Taipei.

Kunqu was listed as one of the Masterpieces of the Oral and Intangible Heritage of Humanity by UNESCO in 2001. Its melody or tune is one of the Four Great Characteristic Melodies in Chinese opera.