Hendrick Conrad Joannes Heusken (January 20, 1832 – January 15, 1861) was a Dutch-American interpreter for the first American consulate in Japan, established at Gyokusen-ji in Shimoda, Shizuoka in the late Edo period. He was assassinated by anti-foreigner rōnin.
Heusken was born in Amsterdam to Joannes Franciscus Heusken, who worked for a soap manufacturer, and Johanna Smit. The family immigrated to the U.S. and became naturalized citizens.
Heusken came to Japan in 1856 to work as the personal assistant and interpreter for Townsend Harris, the first United States Consul General to Japan. On January 14, 1861, while returning to the U.S. legation in Zenpuku-ji from the Prussian legation, he was attacked by a group of anti-foreigner rōnin from Satsuma, including Shōuhei Imuta. Heusken died the following day.