Gyrinodon is an extinct genus of toxodontid notoungulate that lived from the Late Miocene and Early Pliocene in what is now Brazil and Colombia.

The frontal region of the skull passed softly into the anterior portion of the temporal fossa.

Unlike some of its relatives, neither the upper edge of the orbit nor the roof of the nasal cavity were swollen.

Gyrinodon quassus was first described by Hopwood in 1928, based on fossils found in Early Pliocene terrains of Venezuela.

Gyrinodon was a member of the Toxodontidae, a family of well-known notoungulates with heavy and large shapes.