William Wade Ellis (1751 – 1785) was an artist, a naturalist, and a surgeon's mate on Captain James Cook's voyages.
He is known largely from the paintings of natural history subjects that he made during Captain Cook's voyages.
Little is known of his early life, but he was described by David Samwell, surgeon on HMS Discovery, as "a genteel young fellow and of good education".
Owing to financial difficulties, Ellis took up an offer to write an account of Cook's third voyage, published in 1782.
On this voyage, Ellis had an accident at Ostend, Belgium, falling from the mast of the Queen Charlotte.