Tainonautilus is an extinct coiled cephalopod that lived during the Permian and Early Triassic which is included in the nautiloid family Tainoceratidae.

The umbilicus is wide and deep; umbilical shoulders have a prominent keel.

The sides bear curved retrograde ribs or folds that slant to the rear going from the inner (umbilical) rim to the outer (ventral).

The venter, which forms the outer rim has a smooth median sulcus.

Tainonautilus has been found in the Alps in Europe and in the Salt Range in Pakistan.