[en] Sm"3"+ single-doped and Sm"3"+, Dy"3"+ co-doped NaGdTiO_4 phosphors were synthesized via a traditional high temperature solid-state reaction method. The crystal structure was characterized by means of x-ray diffraction. The luminescence properties and energy transfer in Sm"3"+ single-doped and Sm"3"+, Dy"3"+ co-doped NaGdTiO_4 phosphors were systematically studied. The electric dipole-dipole interaction between Sm"3"+ ions was identified as the main mechanism for the concentration dependent fluorescence quenching in Sm"3"+ single-doped samples. It is confirmed that there is almost no energy transfer between Sm"3"+ and Dy"3"+ in Sm"3"+, Dy"3"+ co-doped samples. The introduction of Sm"3"+ can compensate the red emission component and adjust the colorimetric performance of Dy"3"+-doped NaGdTiO_4 phosphors. Moreover, different emitting colors can be obtained from Sm"3"+, Dy"3"+ co-doped NaGdTiO_4 phosphor by changing the excitation pathway.