John Henry Kagey, also spelled John Henrie Kagi (March 15, 1835 – October 17, 1859), was an American attorney, abolitionist and second in command to John Brown in Brown's failed raid on Harper's Ferry.
He bore the title of "Secretary of War" in Brown's "provisional government." At age 24, Kagi was killed during the raid.
He had also been active in fighting on the abolitionist side in 1856 in "Bleeding Kansas".