Knoutsodonta depressa is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusc in the family Onchidorididae.

[2] This species was described from Whitley Bay, Northumberland, England.

It is currently known from Norway south to the Atlantic coast of France and the Mediterranean Sea.

[4] Reports from other parts of the world are doubtful and specimens from Brasil have been described as Knoutsodonta brasiliensis.

[5]