Haloquadratum (common abbreviation: Hqr.) is a genus of archaean, belonging to the family Haloferacaceae. The first species to be identified in this group, Haloquadratum walsbyi, is unusual in that its cells are shaped like square, flat boxes.
This halophilic archaean, discovered in 1980 by A.E. Walsby in the Gavish Sabkha, a coastal hypersaline pool (sabkha) on the Sinai Peninsula in Egypt, was not cultured until 2004.