Acartia hudsonica is a species of marine copepod belonging to the family Acartiidae. This species was originally described as a subspecies of Acartia clausi but subsequent research concluded it is sufficiently distinct to warrant specific status. It is found in shallow coastal habitats along both the Atlantic and Pacific coasts of northern North America This species is similar to A. clausi but lacks the prominent spines on the dorsal part of the posterior body segment (metasome).