Eulagisca is a genus of marine polychaete worms belonging to the family Polynoidae.

The genus includes 5 species which are all found in the Southern and Antarctic Oceans and are notable for reaching a large size - 180 mm or more long - larger than any other species of Polynoidae.

[1] Species of Eulagisca have 35–41 segments and 15 pairs of elytra.

The lateral antennae are undivided and inserted terminally on the prostomium .

There is a distinctive dorsal fold ("nuchal flap" in the taxonomic literature) on segment 2, and unlike the related genus Pareulagisca, in Eulagisca all notochaetae are stout and have blunt tips.