Chromodoris westraliensis is a species of very colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.

A mantle covers the upper parts of the animal and extends to form a skirt at the sides.

The colouring is two (or one) bright blue patches on a black background, with an orange outline.

Two sensory organs, tentacle shaped rhinophores, are orange, and are located at the upper surface of the head.

This species occurs in shallow waters on partially exposed reefs and at depths up to 18 metres.