Pseudopediastrum is a genus of green algae in the family Hydrodictyaceae.

[3] Pseudopediastrum forms flat colonies, termed coenobia, of cells in powers of two, usually four, eight, 16, or 32.

Coenobia are disc-shaped in outline, and marginal cells are drawn out into two lobes or points.

[5] In 2005, molecular phylogenetic analyses showed that Pediastrum sensu lato was paraphyletic with respect to Hydrodictyon.

Therefore, Pediastrum was split up into several genera, including Pseudopediastrum.