Eu2+–Mn2+ codoped yellow-emitting Sr9Sc(PO4)7 (SSP) phosphors have been synthesized by solid-state reactions. The synthesis, structure refinement, and luminescence properties of the obtained phosphor were investigated in detail. The obtained phosphor exhibits a strong excitation band between 250 and 450 nm, matching well with the dominant emission band of a near-UV light-emitting-diode (LED) chip. Upon excitation at 365 nm, the Sr9Sc(PO4)7:Eu2+, Mn2+ phosphor shows strong yellow emissions centered at 510 and 610 nm. The energy transfer mechanism from Eu2+ to Mn2+ in Sr9Sc(PO4)7:Eu2+, Mn2+ has been studied and demonstrated to be a resonant type through a dipole-quadrupole mechanism based on the decay lifetime data. These results indicate that yellow-emitting Sr9Sc(PO4)7:Eu2+, Mn2+ can serve as a promising candidate for application in white-light LEDs.