[6] In the revised classification to create monophyletic genera, the green-fronted hummingbird was one of three species moved to the resurrected genus Leucolia by some taxonomic systems.

[8][9][3] As of that date the Clements taxonomy retains the species in Leucolia and BirdLife International's Handbook of the Birds of the World (HBW) in the earlier Amazilia.

[3][4] AOS and Clements include a third, R. v. wagneri, that the IOC and HBW consider to be a separate species, the cinnamon-sided hummingbird.

Males and females of subspecies R. v. villadai are very similar to the nominate but somewhat larger, and the green of their sides is less extensive giving a white appearance to their underparts.

[11] The nominate subspecies of green-fronted hummingbird is found in southern Mexico from central Guerrero into western Oaxaca.

Very few nests have been found; one was a cup made of whitish plant down covered with green lichens, and placed about 1.8 m (6 ft) above the ground.

[11] The IUCN has assessed the green-fronted hummingbird as being of Least Concern, though its population size is unknown and believed to be decreasing.