Gyroptychius is an extinct genus of osteolepiform lobe-finned fish from the Devonian period.
Gyroptychius was a fast riverine predator with an elongated body about 30 centimetres (12 in) long. As its eyes were relatively small, it is presumed to have hunted by smell rather than sight. Gyroptychius had short jaws which gave it a powerful bite. All its fins except the pectorals were moved to the back to the body, increasing the power of the tail while swimming.