Gardnerella
vaginalis

Gelidibacter
mesophilus

Gemella
bergeri - haemolysans - morbillorum - sanguinis

Geobacillus
caldoxylosilyticus - kaustophilus - lituanicus - pallidus - stearothermophilus - subterraneus - thermocatenulatus - thermodenitrificans - thermoglucosidasius - thermoleovorans - toebii - vulcani

Giesbergeria
giesbergeri - sinuosa

Gillisia
limnaea - mitskevichiae

Glaciecola
mesophila - pallidula - polaris - punicea

Globicatella
sanguinis - sulfidifaciens

Gluconacetobacter
diazotrophicus - europaeus - hansenii - intermedius - johannae - liquefaciens - oboediens - rhaeticus - sacchari - swingsii - xylinus

Gluconobacter
albidus - cerinus - frateurii - oxydans - sp.

Gordonia
bronchialis - rubropertincta - terrae

Gracilibacillus
dipsosauri

Gramella
echinicola

Granulicatella
adiacens - elegans

Grimontia
hollisae

Gulosibacter
molinativorax