特有种（endemic species，指特有性之现象或性质，英文为endemism）是指「因历史、生态或生理因素等原因，造成其分布仅局限于某一特定的地理区域或大陆，而未在其他地方中出现」的物种。有些特有种原来就起源于该地区，这些物种因此又可以称为该地区的固有种或土着种，比如说无尾熊和红袋鼠，都仅产于澳洲，而未在世界上的其他地方发现过，因此两者都是澳洲的固有种动物。有些则是从其他地区迁来的，比如说南美洲的骆马（Lama guanicoe），根据古生物学的数据，它原发生于北美洲，是北美洲的固有种，后来却在原产地绝灭了，现在的驼马只分布在南美洲，成为该洲的特有种。

Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. The extreme opposite of endemism is cosmopolitan distribution. Another term for a species that is endemic is precinctive, which applies to species (and subspecific categories) that are restricted to a defined geographical area.