Single crystals of molybdenum(VI) tricopper(II) tellurium(IV) heptaoxide dichloride hemihydrate, MoCu3TeO7Cl2.0.5H2O, were synthesized via a transport reaction in sealed evacuated silica tubes. All atoms occupy general positions within the triclinic (P1) unit cell. The building units are irregular CuO4Cl and CuO3Cl2 square pyramids, distorted TeO3+1E trigonal bipyramids (E is the lone pair of TeIV) and irregular MoO5 pyramids. The TeO3+1E, CuO4Cl and CuO3Cl2 polyhedra form (110) layers bridged by Mo atoms. The water molecules are located in [100] channels.