Berthella ornata is a species of sea slug, a marine gastropod mollusk in the family Pleurobranchidae.

This is a distinctive pleurobranch up to 70 mm (2.8 in) in length, the dorsal surface bearing reddish or brownish spots overlaying an opaque background that can vary from white to dark red or brown.

B. ornata is slow moving and feeds on sponges at night, often emitting a milky fluid if disturbed.

It is usually found hiding under boulders and stones during the day, with the head and rhinophores retracted under the mantle.

It is found at low tide through the sub-littoral fringe down to 6 metres deep.