Luan Zhi 欒枝 (died 622 BCE), personal name Ji Zhi 姬枝, posthumous title Luan Zhenzi 欒貞子, was a nobleman in the state of Jin 晉 during the Spring and Autumn period 春秋 (770-5th cent. BCE). He was a member of the house of Luan 欒, a grandson of Luan Bin 欒賓 and a son of Luan Cheng 欒成, and was befriended with Prince Chong'er 重耳, the eventual Duke Wen of Jin 晉文公 (r. 636-628).
He therefore supported the enthronement of Prince Chong'er, who lived in exile in the state of Qin 秦, by ensuring his return to Jin with the assassination of Duke Huai 晉懷公 (r. 637). In 633, Duke Wen created the three armies (sanjun 三軍), and Luan Zhi was appointed assistant commander of the Lower Army (xiajun zuo 下軍佐), after being recommended by Zhao Shuai 趙衰 (Zhao Chengzi 趙成子).
A year later, he fought against the troops of Chu 楚 in the battle of Chengpu 城濮, where he feigned a withdrawal and so utterly defeated the army of Chu. He also participated in the campaign against Zheng 鄭 and so paved the way for Duke Wen's raise to hegemonial lord (ba 霸). Under Duke Xiang 晉襄公 (r. 628-621), Luan Zhi clung to the line that the state of Qin could not be attacked, as the nobleman Xian Zhen 先軫 claimed, because the duke of Qin had once supported Duke Wen in exile.