Jan Hendrik Donker Curtius (21 April 1813, Arnhem – 27 November 1879, Arnhem) was the last Director of the Dutch trade in Japan (1852-1855) at Dejima in the harbour of Nagasaki. To negotiate with the Japanese government about a treaty he received the title "Dutch Commissioner in Japan" in 1855 with the permission to wear the uniform of a Navy officer. He studied law at Leiden University.
He arrived at Dejima from Batavia in 1852. He assisted others, including Western negotiators, in the process of adjusting and working through unfamiliar Japanese customs and practices.
Donker Curtius handled in1855 the transfer of HM's Soembing from the Dutch Navy to the Japanese. The ship, renamed Kanko Maru, became Japan's first modern steam warship – a gift from the Dutch King Willem III to the Tokugawa Shogun.
He negotiated a convention with the Japanese in November 1855, changed into the first treaty of Japan with a foreign country by ratification in January 1856. In 1857 he concluded a trade paragraph to be added to the treaty of 1856 which was copied by the Russian Vice Admiral E.V. Putiatin. In 1858 he made the ceremonial visit to Edo as representative of the Dutch king to pay tribute to the Shogun and negotiate a new treaty on the basis of the American Consul Townsend Harris' treaty of that year. He was accompanied by his secretary Dirk de Graeff van Polsbroek. During his stay in Japan he acquired a collection of 111 books on Rangaku, which are today preserved at Leiden University Library. He returned in 1860 to Batavia via Siam, where he concluded a treaty between Siam and The Netherlands, and from there to The Netherlands where he was employed by the Internationale Crediet Maatschappij at Rotterdam.