Hermadionella is a genus of marine polychaete worms belonging to the family Polynoidae, the scaleworms.

Hermadionella contains 3 species which are known from the north-west Pacific and Arctic Oceans from the intertidal to depths of about 200 m.[2] Hermadionella are long-bodied scale worms with 50–60 or more segments and 15 pairs of elytra; the posterior-most 15–20 or more segments are thus not covered by elytra.

The prostomium is bilobed and rounded anteriorly, lacking acute cephalic peaks.

The neuropodial lobe is elongate, tapering to a slightly rounded tip.

The notochaetae have truncate tips and are distinctly thicker than the neurochaetae.