Five new species of the family Lichomolgidae associated with solitary ascidians are described from the east coast of Korea. Two new genera are proposed: Protomolgus n. gen. to incorpotate Protomolgus duplex n. sp. and P. singularis n. sp., and Dontimolgus n. gen. to incorporate Dontimolgus brevicaudatus n. sp. Protomolgus n. gen. characteristically has a four-segmented female maxilliped and a bipartite mandible. Dontimolgus n. gen. possesses a large, tooth-like process on the first maxillary segment and three spines on the third exopodal segment of leg 3. Other two new species described are Lichomolgus infirmus n. sp. and L. pectinatus n. sp.