Joermungandr is an extinct genus of recumbirostran tetrapod from the Late Carboniferous Mazon Creek fossil beds of Illinois.

It currently contains a single species, Joermungandr bolti.

Like many other recumbirostrans, the body is elongated, which is likely an adaptation for fossoriality (digging and living underground).

[1] The genus was named after Jörmungandr, a creature from Norse mythology.

This article about a prehistoric tetrapod is a stub.