Taricha sierrae, commonly known as the Sierra newt, is a medium-sized salamander, with adults measuring 70-90 mm from snout to vent and 125-200 cm in total length. This salamander has usually warty skin, no costal grooves, and a Y-shaped vomerine teeth pattern. It also has relatively large eyes that extend beyond the profile of the head. Terrestrial adults are reddish to brown dorsally and burnt orange to yellow ventrally. The snout, eyelids, and area below the eyes have conspicuous light coloring. The iris is yellow (Petranka 1998).

During the breeding season, males have a smooth skin, an enlarged and laterally flattened tail to swim better, a lighter body color, enlarged cloacal glands, enlarged mental glands, and tiny cornified papillae on the toe tips and hindlimb bases (to aid in grasping females during amplexus) (Petranka 1998).

Hatchlings are light yellow dorsally with two irregular dark, narrow bands on the back (Twitty 1942). Taricha sierrae has dark spots or blotches along the sides of its body, which are more prominent in older larvae. Hatchlings reach 13-14 mm TL (Riemer 1958).
 
The Sierra newt, as Taricha t. sierrae, was historically considered as one of the two subspecies of Taricha torosa, the other being Taricha t. torosa (the Coast Range newt). The two subspecies differ in coloration and geographical distribution. Most notably, the Sierra newt has more conspicuous light coloring of its eyelids and snout, a more reddish dorsal coloration and a more orange ventral coloration, as well as larger eyes that protrude past the profile of the head. The Sierra newt has been suggested as a separate species since 1991 but the nomenclatural change has been consistently challenged. In 2007, the two subspecies were declared "distinct evolutionary lineages" and recognized as the separate species T. torosa (the California newt) and T. sierrae (the Sierra newt), with a contact zone along the southern Sierra Nevada (Kuchta 2007).