Xin Zhui (died 163 BCE), also known as Lady Dai or Marquise of Dai, was the wife of Li Cang, the Marquis of Dai, during the Han Dynasty (206 BCE ??220 CE). She gained fame more than 2,000 years after her death, when her tomb was discovered inside a hill known as Mawangdui, in Changsha, Hunan, China.

After opening the tomb, workers discovered her exceptionally preserved remains alongside hundreds of valuable artifacts and documents. Her body and belongings are currently under the care of the Hunan Provincial Museum, which has allowed occasional international exhibits.