Li Tieguai, also known as Tieguai Li and born as Li Yuan, is a Chinese mythological character and one of the Eight Immortals. Though he is often portrayed as being ill-tempered and irascible, he is benevolent and kind to the poor, sick and the needy, curing and alleviating the pain of others with special medicine from his magical gourd. Li Tieguai was said to have been born during the Yuan Dynasty.

In Chinese folklore, Li Tieguai was said to have originally been Laozi's apprentice, which would have put his birth some time in the sixth century BCE rather than during the Yuan Dynasty. Either way, he is said to have devoted himself to religious contemplation for 40 years, overcoming various tests and tasks Laozi set for him eventually becoming an immortal.

Li Tieguai was said to have been a handsome man once, but during his path towards immortality, there was an incident when his spirit left his body and ascended to Heaven to meet other immortals. While away, his body was cremated, and when Li's spirit returned, he had to enter the corpse of an ugly and disheveled homeless beggar who had just recently starved to death. Li Tieguai is the second most popular of the Eight Immortals, and associated with medicine.