The State of Wu, also known as Gou Wu or Gong Wu, is one of the vassal states during the Western Zhou Dynasty and the Spring and Autumn Period.

The State of Wu is located at the mouth of the Yangtze River east of the State of Chu.

Considered a semi-barbarian state by ancient Chinese historians, its capital is at Gusu, also known as Wu, in modern day Suzhou.

The rulers of the State of Wu have the surname Ji, the same as the Zhou royal family.