Zhenzhu Khan (died October 21, 645), personal name Yi'nan, full regal title Zhenzhupiqie Khan, is a khan of Xueyantuo, under whom Xueyantuo rises from being a vassal of Eastern Tujue to a mighty khanate ruling over northern/central Asia.

During his reign, Xueyantuo largely aligns with China's Tang Dynasty, even though the two states are at odds at times, with the most serious dispute involving Tang's attempt to reestablish Eastern Tujue as a vassal state under the Qilibi Khan Ashina Simo—an attempt that eventually fails due to frequent incursions by Yi'nan's army against Ashina Simo.

Throughout Yi'nan's reign, Xueyantuo remains powerful despite Tang attempts to curb its power, but after Yi'nan's death, a succession dispute between his sons, Bazhuo and Yemang, leads to Bazhuo's killing of Yemang and subsequent internal unrest.

Further, Bazhuo attacks Tang, resulting in a major Tang retaliation campaign that, along with a revolt by the Huige, leads to Xueyantuo's destruction in 646.