John Howard Northrop (1891 nî 7 goe̍h 5 ji̍t – 1987 nî 5 goe̍h 27 ji̍t) sī chi̍t ūi Bí-kok ê hòa-ha̍k-ka. I mā-sī 1946 nî Nobel Hòa-ha̍k Chióng ê ti̍t-chióng-jîn; i ti̍t-chióng ê lí-iû sī for their preparation of enzymes and virus proteins in a pure form.

John Howard Northrop