A xian (simplified Chinese: 仙; traditional Chinese: 僊; pinyin: xiān; Wade–Giles: hsien) is any manner of immortal or mythical being within the Taoist pantheon or Chinese folklore. Xian has often been translated into English as "immortal" or "wizard".

Traditionally, xian refers to entities who have attained immortality and supernatural or magical abilities later in life, with a connection to the heavenly realms inaccessible to mortals. This is often achieved through spiritual self-cultivation, alchemy, or worship by others. This is different from the gods (deities) in Chinese mythology and Taoism.

Xian is also used as a descriptor to refer to often benevolent figures of great historical, spiritual and cultural significance. The Quanzhen School of Taoism defined xiān in various ways, including a metaphorical sense meaning a good or principled person.

Xian have been venerated from ancient times to the modern day in a variety of ways across different cultures and religious sects in China.

In China, "gods (deities)" and "xian" are often mentioned together as "神仙".

Victor H. Mair describes the xian archetype as:

They are immune to heat and cold, untouched by the elements, and can fly, mounting upward with a fluttering motion. They dwell apart from the chaotic world of man, subsist on air and dew, are not anxious like ordinary people, and have the smooth skin and innocent faces of children. The transcendents live an effortless existence that is best described as spontaneous. They recall the ancient Indian ascetics and holy men known as rishi who possessed similar traits.

Xiān were regarded as "personal gods" who had been human and ascended through ascetics, scholarship, or martial arts. Taoists would venerate them, and emulate their example in everyday life.