Euglenophyceae (ICBN) or Euglenea (ICZN) is a group of single-celled algae belonging to the phylum Euglenozoa.

They are distinguished from other algae by the presence of paramylon as a storage product and three membranes surrounding each chloroplast.

Their chloroplasts originated from a secondary endosymbiosis with a green alga, particularly from the order Pyramimonadales,[5] and contain chlorophylls a and b.

[3] Euglenophyceae encompasses three taxonomic groups: the mixotrophic Rapaza viridis and two mainly phototrophic orders, Euglenales and Eutreptiales.

[1][3][6] The classification is as follows (species numbers based on AlgaeBase):[7] Several genera assigned to Euglenophyceae are considered incertae sedis, because the lack of genetic data makes their phylogenetic position unresolved:[3]