Hallipterus is a genus of prehistoric eurypterid classified as part of the family Hardieopteridae.

[1] The carapace was subelliptical, greater in length than in width, with a prominent and unornamented marginal rim.

The eyes were very small, close to each other and separated by a prominent median ridge with large ocelli at the posterior extremity.

[2] Hallipterus contains one valid species, H. excelsior, from the Devonian of New York.

[3] Another species was once recognized from similarly aged deposits in Pennsylvania, "H. lacoanus",[2] but it is today seen as synonymous with H.