Bak Mei (Chinese: 白眉; pinyin: Bái Méi; Wade–Giles: Pai Mei; Cantonese Yale: Baahk Mèih; lit. 'White Eyebrow') is said to have been one of the legendary Five Elders—survivors of the destruction of the Shaolin Monastery by the Qing dynasty (1644–1912)—who, according to some accounts, betrayed Shaolin to the imperial government. He shares his name with the South Chinese martial art attributed to him.

Bak Mei has been fictionalized in Hong Kong martial arts films such as Executioners from Shaolin (1977), Abbot of Shaolin (1979), and Clan of the White Lotus (1980). Bak Mei as a fictional character is better known in the West as Pai Mei, played by Gordon Liu in the Hollywood action film Kill Bill, Vol. 2 (2004).

Accounts of the Five Elders are many and varied, with some versions identifying the traitor as Bak Mei and others as Ma Ning-Yee. In other versions, both elders betray Shaolin, sometimes along with Fung Do-Duk. Still others say that “Bak Mei” was actually a nickname for either Ma Ning-Yee or Fung Do-Duk.

The degree to which stories of the Five Elders are based on historical fact remains unverified. Their ubiquity and widespread popularity can be at least partially attributed to Wuxia novels (such as Wan Nian Qing), as well as the mythology around anti-Qing organizations such as the Heaven and Earth Society, which were spreading rapidly through China in the early 19th century. Whether justified or not, Bak Mei's traitorous reputation led to animosity between practitioners of his namesake martial art and practitioners of martial arts identified with those whom he is accused of betraying.

In the accounts of some Bak Mei practitioners, their founder did not so much betray Shaolin as decline to join their rebellion against the Qing. Other accounts portray Bak Mei as having been banished from Shaolin Temple because he killed several of his fellow monks when he first began practicing his new fighting style. Some Bak Mei practitioners have interpreted this to prove that their founder's style was superior to that of the Shaolin disciples he allegedly killed.

According to legend, Bak Mei played an important part in the downfall of Shaolin temples. Manchu conquered China in 1644. Before then, China had been ruled by the Ming Dynasty, which had been weakened by internal corruption and rebellion. The Manchu dynasty became known as the Qing Dynasty. As part of the Manchu campaign to pacify China, they attacked some Buddhist Shaolin Temples. The leader of the Shaolin Temple, Hong Mei (“Red Eyebrows”) died, leaving his legacy to Chi Thien Su, also known as Jee Sin, one of the five Great Kung Fu Masters. According to some stories another such master, Chu Long Tuyen, the monk who would later become Bak Mei, did not accept this. He believed the Ming had become corrupt and Chi Thien Su would still serve them; Bak Mei would rather serve the foreign Qing Dynasty. Then came the attack against the Shaolin Temple at Quanzhou in Fujian province in 1647. Some sources indicate that this temple was actually in Henan, or that the invading forces recruited help from Tibetan warriors in the attack. The Five Elders survived, however, and soon Chi Thien Su would found a second Shaolin Temple at Nine Lotus Mountain, also in Fujian Province. The Five Kung Fu Masters survived the first destruction of the Shaolin Temple by Qing Imperial forces and sought shelter in another temple, Fujian Temple, but the other monks were massacred. After Bak Mei refused to provide his real name for fear of retribution (against his family and students - if they survived), the Abbott of the temple christened the monk “Bak Mei” - White Eyebrow. According to some stories, Bak Mei betrayed the Ming at this point, taking information about their plot against the Manchu to the Manchu Shunzhi Emperor, then returned with information about the Manchu attack plan to the Shaolin. After the temple was destroyed by the Manchu, Bak Mei left the temple to study Taoism. Bak Mei trained an anti-Imperial attack force but following capture of the force by the Imperials, was forced to teach and lead 50,000 Imperial troops in the second destruction of the Shaolin Temple at Henan to prevent those captured with him from being tortured and killed. There, Bak Mei slew the “invincible” Shaolin leader, Chi Thien Su, in single combat by breaking his neck. He claimed he did this to prevent the massacre of the monks in the temple by the troops who followed him. The tale of Bak Mei's death comes in many forms - it is often claimed that he was poisoned, or slain (in a grand battle) by other martial artists. Bak Mei is often portrayed as a traitor, however, it is important to note that Bak Mei's actions are not always consistent with this. Bak Mei's actions were undertaken, even to the destruction of the temple, with the intention of preventing harm to those who had chosen to follow him. It is possible that if Bak Mei had not aided the Imperial forces, his followers would have been tortured to death.

During the reign of the Kangxi Emperor (r. 1661–1722) in the Qing dynasty, the warriors of the Xilufan revolt were so feared that the two ministers the Kangxi Emperor ordered to end their attacks fled China rather than face either the mercilessness of the Xilu warriors or the displeasure of the emperor, both of which often involved beheading.

It was the 128 monks of the southern Shaolin temple who defeated the army of Xilu over three months in 1673 without suffering a single casualty. However, by doing so the monks had made enemies of those in the Qing army and Qing court who were embarrassed by how easily the Shaolin monks had succeeded where they had failed. Soon rumors began to spread about the threat posed by a power so great that it defeated the entire Xilu army with a force of only 128 monks. This campaign of innuendo was wasted on the Kangxi Emperor, who remained grateful to the monks, but the rumors had their intended effect on his successor, the Yongzheng Emperor (r. 1722–1735), who ordered the temple's destruction.