Xin, King of Hán (died c.March 196 BC), also known as Hán Xin and as Hán Wang Xin, was a noble of the early Han dynasty of China and a descendant of the royal family of Hán during the Warring States period. He was made King of Hán (韓王) in 205 BC by Liu Bang, the founding emperor of the Hàn dynasty, and became a vassal of the Hàn Empire. In 201 BC, after he was suspected of conspiring with the Xiongnu against the Hàn Empire, he defected to the Xiongnu and was eventually killed in a battle between the Hàn Empire and Xiongnu in 196 BC.

Hán Xin was a grandson of King Xiang of Hán during the Warring States period. Around 207 BC, he joined Liu Bang's rebel group in Henan and worked together with other rebel groups throughout China to eventually overthrow the Qin dynasty in 206 BC. After the fall of the Qin dynasty, China was divided into the Eighteen Kingdoms and Liu Bang was made the King of Hàn (漢王), with his domain in the remote Bashu region (present-day Chongqing and Sichuan).

In late 206 BC, Liu Bang led his army out of Bashu to attack the Three Qins. This marked the beginning of the Chu–Han Contention – a four-year power struggle for supremacy over China between Liu Bang and his rival Xiang Yu. At that time, the restored Hán kingdom was being ruled by Zheng Chang, who had been appointed King of Hán (韓王) by Xiang Yu. Liu Bang promised to help Hán Xin become the King of Hán, and sent him with some troops to attack Zheng Chang's kingdom. By the following year, Hán Xin had conquered more than ten cities in the Hán kingdom, forced Zheng Chang to surrender, and replaced Zheng Chang as the King of Hán.

In 204 BC, after Liu Bang was defeated by Xiang Yu at the Battle of Xingyang, Hán Xin was captured by Xiang Yu and forced to surrender. Later, he managed to escape and return to Liu Bang's side. Hán Xin was reinstated as the King of Hán and became a vassal of the Hàn Empire after Liu Bang defeated Xiang Yu in 202 BC and became emperor of the Hàn dynasty. Hán Xin was granted the lands around Yingchuan as his vassal kingdom, with the capital at Yangzhai (陽翟; present-day Yuzhou, Henan).

In 201 BC, Liu Bang realised that the Hán vassal kingdom was in a strategic location and might pose a threat to his Hàn Empire if Hán Xin were to turn against him. As such, he relocated the Hán vassal kingdom to Taiyuan Commandery with the capital at Jinyang (晉陽; present-day Taiyuan, Shanxi) under the pretext of sending Hán Xin to defend the northern border from the Xiongnu. When Hán Xin requested to have his capital at Mayi (present-day Shuozhou, Shanxi), the emperor approved his request.

Shortly after that, the Xiongnu attacked Mayi, leading Liu Bang to suspect that Hán Xin was secretly conspiring with the Xiongnu against him. The emperor then issued an imperial edict to reprimand Hán Xin for his failure to prevent the Xiongnu attack. Hán Xin knew that the emperor doubted his loyalty and feared that he and his family might be exterminated, so he betrayed the Hàn Empire and sided with the Xiongnu.

In late 200 BC, Liu Bang personally led his forces to attack Hán Xin and forced him to retreat to Xiongnu territory. However, Liu Bang eventually had to retreat after he was defeated by the Xiongnu at the Battle of Baideng. In the following years, Hán Xin and the Xiongnu constantly raided the Hàn Empire's northern border.

In 197 BC, Hán Xin sent Wang Huang (王黃) to convince Chen Xi to rebel against the Hàn Empire, which the latter did.