Tetrallantos is a genus of green algae in the Scenedesmaceae family.

It is a component of the phytoplankton or metaphyton of freshwater habitats such as ponds and lakes[1] It has been found worldwide,[2] but appears to be somewhat rare.

[1] Tetrallantos consists of colonies (called coenobia) of four or eight cells.

In the center of the colony, two cells lie in one plane with their ends touching each other; the other cells are attached to those ends and are curved away in a different plane.

In each cell, four (sometimes two or eight) spores are formed per sporangium, and are organized into the shape of coenobia.