Hypselodoris bullockii is a species of colourful sea slug or dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.

Hypselodoris apolegma, which looks similar to this species (and is distinguished by a reticulate pattern gradually merging in to the pinkish purple [6][7]), was previously assumed to be possibly a different colour form of H.

Hypselodoris apolegma is found throughout the western Pacific from Japan (Okinawa), the Philippines, Indonesia Malaysia (Sabah) whereas H. brycei, is found only in Western Australia (Houtman Abrolhos Islands to the Exmouth Region and Dampier Archipelago).

Hypselodoris bullockii is considered to be widespread in the western and central Pacific, from Japan, Taiwan, Hong Kong, the Philippines, Indonesia, Malaysia, eastern Australia, the Marshall Islands and New Caledonia, whereas H. melanesica is known only from Papua New Guinea and the Solomon Islands, both of which are areas where H. bullockii is absent.

Hypselodoris variobranchia is apparently restricted to Japan (Okinawa), Taiwan, the Philippines, Malaysia, Indonesia and Queensland, Australia.