达尔文四号（Darwin IV）是一个虚构的行星，最初出现在美国科幻作家韦恩·巴罗（Wayne Barlowe）的作品「Expedition: Being an Account in Words and Artwork of the 2358 A.D. Voyage to Darwin IV」中。该行星有着跟地球类似的环境，但却没有我们一般熟知的海洋，距离地球约 6.5 光年，一天等于地球约 26.7 个小时；在几百万年前被海洋覆盖，后来在经过重大气候变迁下，大部分的海洋蒸发形成了浓密的大气层，原本被海洋淹没的地区变成了山脉、高原、沙漠和草原，同时也繁衍出了许多奇特的动物。

Darwin IV is a fictional planet that was the subject of Wayne Barlowe's book Expedition and the television special, Alien Planet, based on Expedition. Although the details of the discovery and exploration of Darwin IV differ in the two presentations, both are essentially the same in their depiction of the planetary environment and its native life-forms, whose abundance and variety prompt the name Darwin.