| Named By: | Erik Jarvik in 1952 |
| Time Period: | Late Devonian, 365 Ma |
| Location: | Eastern Greenland |
| Size: | 60 centimetres long |
| Diet: | unavailable |
| Fossil(s): | Initially only skull fragments, further fossils have been discovered making it one of the most completely preserved species. A very well preserved specimen was discovered in 1987 by Jennifer A. Clack |
| Classification: | | Chordata | Tetrapoda | Amphibia | Labyrinthodontia | Ichthyostegalia | |
Acanthostega (meaning "spiny roof") is an extinct genus of stem-tetrapod, among the first vertebrate animals to have recognizable limbs. It appeared in the late Devonian period (Famennian age) about 365 million years ago, and was anatomically intermediate between lobe-finned fishes and those that were fully capable of coming onto land.