Gonium

thumb|right|240px|Gonium colony of 16 cells at nominal magnification of 450x.

Gonium (Greek: γωνία gonia, "angle" or "corner") is a genus of colonial green algae, a member of the order Chlamydomonadales. The genus was first described by Otto Friedrich Müller in 1773, and is among the most common types of algae found in freshwater habitats. It has a cosmopolitan distribution.