Nathaniel Portlock (c. 1748 – 12 September 1817) was a British ship's captain, maritime fur trader, and author.

On Cook's third voyage, furs obtained in present-day British Columbia and Alaska sold for good prices when the expedition called at Macao.

After two years of plying the waters, Portlock and Dixon departed North America, reaching Macao in November 1788.

[6] On their return Portlock and Dixon published an account of the voyage, based in part on letters written by William Beresford, the trader on the expedition.

[1] Returning to the Royal Navy in 1791, Portlock was appointed to command the brig HMS Assistant, which accompanied Bligh on his second voyage to transport breadfruit plants from Tahiti to the West Indies.