Scientists at the Natural History Museum in London have officially called the insect Nelloptodes gretae to honour the 16-year-old Swedish activist's "outstanding contribution" in raising global awareness of climate change.
The arthropod, which has no eyes or wings, is less than 1mm long and belongs to the Ptiliidae family - which is made up of some of the world's smallest beetles.
Dr Michael Darby, a scientific associate at the Natural History Museum, said: "I chose this name as I am immensely impressed with the work of this young campaigner and wanted to acknowledge her outstanding contribution in raising awareness of environmental issues."
The beetle was first found in 1965 by British naturalist Dr William C Block in Nairobi, Kenya.
His collection was donated to the Natural History Museum in 1978 and the beetle was spotted by Dr Darby while he was studying the museum's Spirit Collection.
Dr Max Barclay, senior curator in charge of Coleoptera at the Natural History Museum, said: "The name of this beetle is particularly poignant since it is likely that undiscovered species are being lost all the time, before scientists have even named them, because of biodiversity loss - so it is appropriate to name one of the newest discoveries after someone who has worked so hard to champion the natural world and protect vulnerable species."
The beetle has been featured in The Entomologist journal's monthly magazine.
Ms Thunberg was nominated for the Nobel Peace Prize in 2019, which was later awarded to Ethiopia's Prime Minister Abiy Ahmed.