古兔（Palaeolagus）是已灭绝的兔科。

古兔很像现今的兔，长25厘米。古兔后肢较短，故可能适合奔跑，但未必能够跳跃。

Palaeolagus ('ancient hare') is an extinct genus of lagomorph. Palaeolagus lived in the Oligocene period which was about 33-23 million years ago. The earliest leporids described from the fossil record of North America and Asia date to the upper Eocene some 40 million years ago. Selective pressure ostensibly drove them to become ever faster and better at running and jumping. Other fossil finds from Asia indicate more primitive progenitors of Palaeolagus existed in the lower Eocene; this pushes the likely date of divergence of rabbit-like and rodent-like lagomorphs back to more than 50 million years ago.