The purpose of this work is to develop a single-phase phosphor emitting white light under the excitation of near UV light, targeted at the possible application in white light emitting diodes. Our rationale is to employ a host containing noncentrosymmetric coordination sites for rare earth, therefore the f-f absorptions in the near UV range could be enhanced. Indeed, YGa₃(BO₃)₄ is such a host where Y³⁺ is in a twisted triangluar prism and could be substituted by various rare earth elements. The photoluminescence of Dy³⁺ and Tm³⁺ were investigated in Y_1-xDy_xGa₃(BO₃)₄ (0 ≤ x ≤ 0.10) and Y_1-yTm_yGa₃(BO₃)₄ (0.01 ≤ y ≤ 0.10), whose phase purity was confirmed by powder X-ray diffraction. Dy³⁺ emits yellowish white light and Tm³⁺ emits blue light under their respective f-f excitations (350 and 358 nm). The optimal concentrations in the singly-doped phosphors are 7 and 3 atom%, respectively. When co-doping Dy³⁺ and Tm³⁺ in YGa₃(BO₃)₄, there was no energy transfer between them. Eventually, a white light emission could be obtained with the CIE coordinates of (0.325, 0.329) in Y_0.91Dy_0.07Tm_0.02Ga₃(BO₃)₄ under the excitation of 364 nm.