A new copepod species, Cletocamptus koreanus, is described from estuaries and salt marshes on south and southwest coasts in Korea. Cletocamptus koreanus n. sp. evidently belongs to C. deitersi species group in sharing 6-segmented antennule, 3 setae on antennary exopod, leg 1 with endopod shorter than exopod, and 2+1 inner setae on the third exopodal segments of legs 3-4. However, C. koreanus is distinguished from its allied congeneric species by different setal armatures of mandibular palp, antennary exopod, endopod of female leg 2 and the third exopodal segments of legs 3-4, and relative length and shape of apophysis of male leg 3 enp 2. Description and taxonomic accounts of the new species are presented herein, with detailed illustrations and scanning electron microscope photomicrographs. Discussion on the affinities with other species of C. deitersi group are provided, along with brief comments on the morphological discrepancies between the new species from Korea and other Asian species from China and India.