Nembrotha aurea is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusk in the family Polyceridae. It was first described in 2008.
The type locality of this species is Msimbati, Mtwara Region, Tanzania. It is known from the western Indo-Pacific Ocean.
Nembrotha aurea is a large nembrothid that grows to at least 30 mm in length. The colour is white or creamy, overlaid with undefined patches of yellow and orange. The body is marked with brown longitudinal lines, the width and quantity of which vary from specimen to specimen, ranging from many thin evenly-spaced lines, to broad lines that may converge into a single dorsal brown patch between the rhinophores and gills. The rhinophore clubs and gill pinnae are a bright red. The rhinophore sheathes and gill stalks are commonly coloured a combination of purple and bright electric blue, but in some specimens blue-purple markings are faint and instead mostly white.
This species is commonly confused with some variants of Nembrotha purpureolineata. The most reliable means of telling them apart is that N. aurea always has two dorsal patches of vibrant orange, one patch between rhinophores and gills, and another patch behind the gills. N. purpureolineata only has a single dorsal patch of orange, between the rhinophores and gills.
Nembrotha aurea eats colonial ascidians.