Duke Huan of Tian Qi (Chinese: 田齊桓公; pinyin: Tián Qí Huán Gōng; 400–357 BC) was from 374 to 357 BC ruler of the State of Qi, a major power during the Warring States period of ancient China. Duke Huan's personal name was Tian Wu (田午), and ancestral name Gui (). His official posthumous title was simply Duke Huan of Qi, but he is commonly called Duke Huan of Tian Qi to be distinguished from the original Duke Huan of Qi from the House of Jiang, who was the first of the Five Hegemons of the Spring and Autumn period.

Duke Huan was born in 400 BC, during the reign of Duke Kang, the last Qi ruler from the House of Jiang. In 386 BC Duke Kang was deposed by Duke Huan's father Duke Tai of Tian Qi, the first Qi ruler from the House of Tian. Duke Tai died in 384 BC and was succeeded by his son Tian Yan, Duke Huan's elder brother. In 375 BC Duke Huan murdered Tian Yan and his son Tian Xi, and usurped the throne.

Duke Huan ruled through a period of war and instability. In the first five years of his reign, Qi was invaded by the states of Lu, Wei, Wey, and Zhao on separate occasions. And besides murdering his brother and nephew, the Bamboo Annals also records that he killed his mother in the 11th year of his reign. Although his grandson King Xuan is generally credited with the establishment of the Jixia Academy, other Chinese sources trace it to Duke Huan.

Duke Huan reigned for 18 years and died in 357 BC, at the age of 43. He was succeeded by his son Tian Yinqi, under whose reign Qi would become the most powerful state of China. Yinqi would also be the first ruler to declare himself King of Qi, and is posthumously known as King Wei of Qi.

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