A new species, Goniopsyllus dokdoensis, is described from the adjacent waters of Dokdo Island in the East Sea of Korea. The new species is closely related to G. clausi in the triangular shape of the rostrum, the length of the thoracopod 5 exopod, and the constricted genital double somite. However G. dokdoensis is distinguished from G. clausi by its smaller body size, genital field with additional pores adjacent to the copulatory pore, urosomites without dorsal ornamentation, and differences in the length of caudal setae. Also, the sixth pair of legs in the male has two setae at the outer distal corner of each lobe. This study is the first to report the presence of the genus Goniopsyllus in Korean waters.