文昌鱼属（英文名：Lancelet，学名：Branchiostoma）是头索纲文昌鱼目的其中一个属，也是文昌鱼科下唯一一个属及模式属，包括有多种文昌鱼。

Branchiostoma is one of the few living genera of lancelets (order Amphioxiformes). It is the type genus of family Branchiostomidae.

These small vaguely eel- or snake-like animals are close relatives of vertebrates. The scientific name means "gill-mouth", referring to their anatomy – unlike vertebrates, they do not have a true head (with a skull capsule, eyes, nose, a well-developed brain etc.), but merely a mouth adjacent to the gill-slits, with the slightly enlarged anterior end of the dorsal nerve cord above and in front of them.