The family includes the most well-known euglenoid genus, Euglena, as well as other common genera like Phacus and Lepocinclis.

[2] If classified as an alga, it would fall under the International Code of Botanical Nomenclature (ICBN) and its correct name would be Euglenales; if classified as a protozoan, it would fall under the International Code of Zoological Nomenclature (ICZN) and would be called Euglenida.

[2] Euglenales consists mostly of freshwater organisms, in contrast to its sister Eutreptiales which is generally marine.

[4] In its current circumscription, Euglenales is monophyletic, consisting of two sister clades corresponding to Euglenaceae and Phacaceae.

[5] A cladogram representing the phylogenetic relationships is shown below:[1] Euglenaceae Phacaceae Eutreptiales Rapazida