Meiolania had an unusually shaped skull that sported many knob-like and horn-like protrusions. Two large horns faced sideways, giving the skull a total width of 60 centimetres (2.0 ft), and would have prevented the animal fully withdrawing its head into its shell. The tail was protected by armored 'rings', and sported thorn-like spikes at the end. The body form of Meiolania may be viewed as having converged towards those of dinosaurian ankylosaurids and xenarthran glyptodonts.
The animal was rather large, measuring 2.5 metres (8.2 ft) in length, making it the second-largest known nonmarine turtle or tortoise, surpassed only by Megalochelys atlas from Asia, which lived in the Pleistocene. It lived in Australia, Lord Howe Island, New Caledonia and Vanuatu.
The Meiolania specimens once living on New Caledonia and Lord Howe Island were much smaller than their giant relatives from the Australian continent.
Meiolania turtles fed on plants. Because the remains known by 1925 were found close to beaches, it was thought to be aquatic. It is now known to have been terrestrial.