Emperor Gong of Sui (605 – 14 September 619), personal name Yang You, is an emperor of the Chinese Sui Dynasty.

Traditionally, he is considered the last emperor of the dynasty because he is the one who formally yields the throne to the founding emperor to the succeeding Tang Dynasty, Emperor Gaozu of Tang (Li Yuan), although after him, his brother Yang Tong claims the throne and continues to do so until 619.

Li had rebelled against the rule of Yang You's grandfather Emperor Yang of Sui in 617 and captured the capital Chang'an later that year, seizing Yang You and declaring him emperor, although only the commanderies under Li's control recognized him as emperor; the rest of the commanderies continue to recognize Emperor Yang as emperor.

In 618, after news arrives that Emperor Yang had been killed by the general Yuwen Huaji, Li has the young emperor yield the throne to him.

The former emperor dies the following year, probably on the new emperor's orders.