Qín ([tɕʰǐn]) (秦) is a common Chinese surname. "Qin" is the hanyu pinyin romanization of the surname for Mandarin, the common dialect of China; other romanizations of the surname include Chin and Jin in Mandarin, Ceon and Cheun in Cantonese, and Tần (or Tan when commonly written without accent in ASCII) in Vietnamese. People with this surname are most commonly found in Henan, Shaanxi, Shandong, Sichuan, Hubei and Hebei.^[1] It is the 18th name on the Hundred Family Surnames poem.

Other surnames romanized as "Qin" include 欽/钦.

According to the Shuowen Jiezi, the character for Qin is a compound ideogram which combined two characters: chong 舂 "to pound", and he 禾 "grain".^[2] The character originally refers to Qin Valley (秦谷) in Longxi near Tianshui, Gansu and became the name of that area. The area was granted to Feizi, a descendants of Gao Tao, by King Xiao of Zhou as a fief in the 9th century BC, which then grew into the state of Qin. In the 3rd century BC, the state of Qin unified China and became the first imperial dynasty under Qin Shi Huang. After the fall of the dynasty in 206 BC, the descendants of Qin royalty, whose ancestral name was Yíng (Chinese: 嬴), was said to have adopted the surname Qin.^[1] Many people sought to identify themselves with the Qin long since the fall of the Qin dynasty; in Japan, the Hata clan of Japan claims descent from a branch of the Qin royal family, "Hata" being the native Japanese reading for the character "Qin".^[3]

Another origin came from the Qin City (秦邑; present-day Fan County, Henan) in the state of Lu (鲁). During the early Zhou dynasty in the 10th century BC, Boqin the son of the Duke of Zhou, originally surnamed Ji (姬), was given the state of Lu, and his descendants who were assigned to the Qin estate adopted the name of their place of residence as their surname.^[4]

After the opening of the Silk Road in the 2nd century BC, Daqin (大秦, Great Qin) was the name used by the Han Chinese for the Roman Empire. Some people to the west of China arriving via the Silk Road was therefore said to have adopted the surname Qin.^[5] Various non-Han people of China also took "Qin" as their surname, such as the Mongols, the Daurs, the Manchus, and the Jurchen Moyan (抹捻 during the Jin dynasty and 穆颜 during the Manchu period).^{[citation needed]}

Ancient Chinese texts recorded that one of the friends of the legendary sage king Emperor Shun (23rd century BC) was named Qin Buxu (秦不虛). However, no record exists of the later lineages of this Qin Buxu.