Naso tergus is a species of marine ray-finned fish belonging to the family Acanthuridae, the surgeonfishes, unicornfishes and tangs.

Naso tergus was first formally described in 2011 by Ho-Hsuan Ching, Shen Kang-Ning and Chang Chi-Wei with its type locality given as off Nanfango in Ilan in nortrheastern Taiwan at a depth of 70 to 80 m (230 to 260 ft).

The authors chose the Latin word tergus as its specific name, this name means "hide".

[7] There is a pair of elliptical bony plates on each side of the caudal peduncle.

[7] Naso tergus has been recorded from Taiwan, southern Japan and the Philippines as depths between 70 and 80 m (230 and 260 ft).