Zhang Sanfeng (Simplified Chinese: 张三丰; Traditional Chinese: 張三丰; Pinyin: Zhāng Sānfēng; Wade-Giles: Chang San-feng, variant 張三豐, pronounced the same) was a semi-mythical Chinese Taoist priest who is believed by some to have achieved immortality. This is said variously from either the late Song Dynasty, Yuan Dynasty or Ming Dynasty. His name was Zhang Junbao 張君寶, before he became a Taoist.

As a legendary cultural hero, Zhang Sanfeng is credited by modern practitioners as having originated the concepts of neijia 內家; soft, internal martial arts, specifically Tai Chi Chuan, as a result of a Neo-Confucian syncretism of Zen Buddhist Shaolin martial arts combined with the principles of his Taoist mastery of Taoist Tao Yin (neigong). He is also associated in legend with the Taoist monasteries at Wudang Mountains in Hubei province. Stories from the 17th century onward gave him credit for the development of internal martial arts. In the 19th century and later, stories credit him for Tai Chi Chuan.

Zhang Sanfeng is also said to have been an expert in the White Crane and Snake styles of Chinese martial arts, as well as in the use of the Chinese straight sword or jian. According to relatively late (19th century) documents preserved within the Yang and Wu family's archives, the name of Zhang Sanfeng's master was Xu Xuanping 許宣平, who was said to be a Tang dynasty hermit poet and Taoist Tao Yin expert.

The Tai Chi Chuan families who ascribe the foundation of their art to Zhang traditionally celebrate his birthdate as the 9th day of the 3rd Chinese lunar month. Owing to his legendary status, his name frequently appears in Chinese novels and Wuxia films of swordsmen as a spiritual teacher and master of martial arts.