Anacondas or water boas are a group of large boas of the genus Eunectes. They are a semiaquatic group of snakes found in tropical South America. Three to five extant and one extinct species are currently recognized, including one of the largest snakes in the world, E. murinus, the green anaconda.

The Boinae are a purported subfamily of boas found in Central and South America, as well as the West Indies. In the Integrated Taxonomic Information System (ITIS), Boinae is considered an invalid synonym of Boidae.