A novel phosphor K2Gd(WO4)(PO4):Tb was prepared via a solid-state reaction. The crystal structure of K2Gd(WO4)(PO4) as a new host matrix for luminescence was defined to be the orthorhombic system with space group Ibca (73). Visible quantum cutting under Tb3+ 4f(8)-4f(7)5d(1) excitation and host excitation in K2Gd(WO4)(PO4):Tb3+ via a downconversion was identified. In order to rationalize the quantum cutting effect, the proper mechanism was proposed. According to calculations, the quantum efficiency was up to 183.2% and 176.4% under excitation at 235 nm and 150 nm, respectively. When compared with Zn2SiO4:Mn2+ (P1-G1S), KGWP:0.5Tb(3+) is slightly less bright over 450-650 nm but has a shorter decay time. (C) 2013 Elsevier B.V. All rights reserved.