Zhu Bajie (豬八戒 WG: Chu Pa-chieh aka 豬悟能 Zhu Wuneng or Chu Wu-neng) is one of the three helpers of Xuanzang in the classic Chinese novel Journey to the West.

He looks like a terrible monster, part human and part pig, who often gets himself and his companions into trouble by his laziness, his gluttony, and his propensity for lusting after pretty women. His Buddhist name Zhu Wuneng (豬悟能) given by bodhisattva Guan Yin means "pig (reincarnate) who is aware of ability", a reference to the fact that he values himself insomuch as to forget his own grisly appearance. His master gave him the nickname Bajie which means "eight restraints" to remind him of his buddhist diet. He is often seen as the most outgoing of the group. In the original Chinese novel, the monkey king addresses him as dai1zi0 (獃子) all the time which means "idiot". Even Xuanzang calls him idiot occasionally. Even the author referred to him as the idiot in the narratives in the novel.

Zhu Bajie originally held the grandiose title of Tianpeng Marshall (天蓬元帅), with command over 10,000 heavenly troops. He was banished, however, for his misbehaviour. Once at a party organized for all the significant figures in Heaven, Bajie saw the Goddess of the Moon for the first time and was captivated by her beauty. Following a drunken attempt to get close with her, she reported this to the Jade Emperor and thus he was banished to earth. In some retellings of the story, his banishment is linked to the downfall of the monkey king Sun Wukong. In any case, he was exiled from heaven and sent to be reincarnated on earth, where by mishap he fell into a pig farm and was reborn as his present state.

In the earlier portions of Journey to the West, Sun Wukong and Xuanzang come to a village and find that a daughter of a wealthy man has been kidnapped and the abductor has left a note demanding marriage. After some investigations Wukong finds out that Bajie is the 'villain' behind this. He fights with the Monkey, but ends the fight when he learns that Wukong is a servant of Xuanzang, revealing that he has been recruited by the bodhisattva Guan Yin to join Xuanzang's pilgrimage and make atonements for his sins (those that had got him thrown out of heaven, and the many he had racked up since).

Like his fellow disciples, Bajie has supernatural powers and being a former general in Heaven he is not to be trifled with. He knows 36 transformations.

At the end of the novel, most of Zhu Bajie's fellow pilgrims achieve enlightenment and become buddhas or arhats, but he does not; although much improved, he is still too much a creature of his base desires. He is instead rewarded for his part in the pilgrimage's success with a job as Cleanser of the Altars and all the leftovers he can eat.

As a weapon he wields a powerful nine tooth iron rake from heaven.

In the manga Dragon Ball / Dragon Ball Z and the anime Dragon Ball and Dragon Ball Z, there is a "pig" named Oolong which is loosely based on Zhu Bajie — he is greedy, ugly, stupid and has the shape-changing ability. Unlike Zhu Bajie, he is not as important to the plot, especially in the later part of the Dragon Ball manga (known as Dragon Ball Z in the United States).

In the manga and anime Saiyuki, a major character named Cho Hakkai is loosely based on Zhu Bajie. Hakkai, being gentle, polite, and hardly resembling anything but a human, is nothing like Bajie.