Euglena gracilis is classified within the Phylum Euglenozoa within the Kingdom Protista. Here's a breakdown of its classification:

* Domain: Eukarya

* Kingdom: Protista

* Phylum: Euglenozoa

* Class: Euglenophyceae

* Order: Euglenales

* Family: Euglenaceae

* Genus: Euglena

* Species: Euglena gracilis

It's important to note that the classification of organisms can change as scientific understanding evolves.