Duke Huan of Lu (Chinese: 魯桓公; pinyin: Lǔ Huán Gōng, died 694 BC) was from 711 to 694 BC the 15th ruler of the State of Lu during the Spring and Autumn period of ancient China. His ancestral name was Ji (), given name Yun (允) or Gui (軌), and Duke Huan was his posthumous title.

Duke Huan was the son of Duke Hui of Lu and his main wife Zhong Zi (仲子), daughter of Duke Wu of the State of Song. Duke Hui also had another son, Xigu (later Duke Yin of Lu), whose mother was a concubine. Although Xigu was the older son, Duke Huan was made the crown prince owing to the higher status of his mother.

In 723 BC Duke Hui died after 46 years of reign. Although Duke Huan was the crown prince, he was then a little boy and his older half-brother Duke Yin ascended the throne with the understanding that he would rule as a regent until Duke Huan grew up.

In 712 BC, Duke Yin's brother Prince Hui suggested Duke Yin to kill Duke Huan and permanently take the throne, but Duke Yin refused. Afraid that he would be killed if the word leaked out, Prince Hui went to Duke Huan and falsely accused Duke Yin of planning to kill him, offering to kill Duke Yin first. Duke Huan agreed. In the eleventh month of that year Prince Hui had Duke Yin assassinated when he was making sacrificial offerings, and Duke Huan ascended the throne as planned.

In 709 BC, Duke Huan married Wen Jiang, daughter of Duke Xi of Qi, one of the most powerful states during the Spring and Autumn period. Three years later, Wen Jiang gave birth to a boy. The boy had the same birthday as his father, therefore he was given the name Tong, meaning "the same". Tong was made Crown Prince of Lu.

In 696 BC, the State of Zheng was in turmoil. After trying unsuccessfully to kill the powerful minister Zhai Zhong, Duke Li of Zheng fled and Zhai installed Duke Li's half-brother Duke Zhao of Zheng on the throne. Duke Huan of Lu and Duke Zhuang of Song attacked Zheng in an attempt to restore Duke Li, but were defeated.

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