<p>M₅(PO₄)₃Cl: Eu²⁺, Mn²⁺(M = Ca, Sr, Ba) phosphors were prepared by solid-state reaction at different high temperatures in reduced atmosphere. The crystal structure, photoluminescence emission(PL)/ photoluminescence excitation(PLE) spectra, luminescence properties and energy transfer effects were studied. From the PL/PLE spectra under the excitation at 390&#xa0;nm, the excitation bands of Mn²⁺ were found to overlap with the emission bands of Eu²⁺. Furthermore, the overlapping degree in Sr₅(PO₄)₃Cl: Eu²⁺, Mn²⁺phosphors were observed to be broader than that of Ca₅(PO₄)₃Cl: Eu²⁺, Mn²⁺phosphors. Of Eu²⁺, Mn²⁺ co-doped M₅(PO₄)₃Cl (M = Ca, Sr, Ba) phosphors, the Ca₅(PO₄)₃Cl: Eu²⁺, Mn²⁺ and Sr₅(PO₄)₃Cl: Eu²⁺, Mn²⁺ showed two emission peaks respectively: the blue and orange-reddish bands, which can be assigned to the 4f → 5d transition of Eu²⁺ and ⁶A₁(⁶S) to ⁴E(⁴D),⁴T₂(⁴D), [⁴A₁(⁴G),⁴E(⁴G)], ⁴T₂(⁴G) and ⁴T₁(⁴G) transition of Mn²⁺. The decay time for Eu²⁺ was found to decrease with increase of Mn²⁺ content, which is a strong evidence for the energy transfer from Eu²⁺ to Mn²⁺. The transfer efficiency approaches its maximum value of 0.05 in Ca_4.97−n(PO₄)₃Cl:0.03Eu²⁺, nMn²⁺. For Sr_4.9−n(PO₄)₃Cl:0.1Eu²⁺, nMn²⁺, the value is 0.47. The Eu²⁺, Mn²⁺ co-doped M₅(PO₄)₃Cl (M = Ca, Sr) may have a potential application for white LEDs.</p>