Aglaothamnion is a genus of algae belonging to the family Callithamniaceae.

[1] The genus was first described by Genevieve Feldmann-Mazoyer in 1941,[1][2] and the type species is Aglaothamnion furcellariae (currently accepted as Aglaothamnion tenuissimum).

[1] The genus has cosmopolitan distribution.

[3]