Hong Tianguifu (洪天貴福 in pinyin: hong2 tian1 fu2 gui4) (1848 - 1864), also called Hong Tiangui and in Qing historical record, Hong Futian (洪福瑱 fu2 tian4), was the second and last king of the Heavenly Kingdom of Taiping. He is popular referred to the Junior Lord (幼主). Officially, like his father, he was the King of Heaven (天王). To differentiate, he is also called the Junior King of Heaven (幼天王).

Born to Hong Xiuquan and Lai-shi (賴氏), Hong succeeded his father at sixteen and was not respected like his father by the princes, and he was spoken of lowly. In Zhong Prince Li Xiucheng Describes Himself (《忠王李秀成自述》), the autobiographical account of a prince of the Heavenly Kingdom written shortly before his execution, Hong Tianguifu was described as "inexperienced," "spoiled," and "incapable." Also, Hong Tianguifu never rode a horse, which was essential for leaders and commanders in wars.

Four months after his coronation, the kingdom was destroyed by Qing Dynasty. He escaped to Hu District (湖州), Zhejiang, and rendezvoused with his uncle, Hong Rengan (洪仁玕), Gan Prince (干王). Together, they attempted to escape to Shi Town (石城) or Nanchang (南昌), Jiangxi, but he got caught on his way by Qing soldiers and was killed at the age of sixteen.

A glimpse of Hong Tianguifu's character can be seen by his remarks before his execution: "Guangdong isn't a nice place, I don't wanna go back. I only wanna study with Old Master Tang in Hunan, then become a first-degree scholar." (“廣東地方不好，我也不愿回去了，我衹愿跟唐老爺到湖南讀書，想進秀才。”) This apparently innocent, pointless and irrelevant comment was considered by some as a desperate and futile attempt to avoid his untimely death by fooling the executioner into confusing his identity. It may have been his utter lack of understanding of what was happening to him, and to his lost kingdom.

Despite the short time he was a king, he was issued a official jade seal (玉璽 yu4 xi3), which is an exhibit in the Hong Kong Museum of History (香港歷史博物館) [1].

Hong Tianguifu's name is unique, in that it contains a three- character given name, whereas almost all Chinese given names have just one or two characters.