A series of Ce3+ and Eu2+ co-doped SrSi2O2N2 phosphors, whose features qualify them for consideration in white-light UV or blue light-emitting diodes (LEDs), was synthesized via a high temperature solid-state reaction under a reductive atmosphere. The dependence of luminescence properties of the produced powders on the concentration of an activator (Eu2+) and a coactivator (Ce3+) was investigated. The experimentally recorded luminescence spectra and the calculations of the efficiency of energy transfer from Ce3+ to Eu2+ and the critical distance between Ce3+ and Eu2+ suggest a resonance-type energy-transfer mechanism from Ce3+ to Eu2+ due to dipole-dipole interactions.