We report the design and properties of hybrid white-light-emitting nanophosphors obtained by electronic coupling of defect states in colloidal Ga2O3 nanocrystals emitting in blue-green with selected organic molecules emitting in orange-red. Coupling between the two components is enabled by the nanocrystal's size-dependent resonance energy transfer, allowing the photoluminescence chromaticity to be precisely tuned by changing the nanocrystal size and selecting the complementary organic dye molecule. Using this approach, we demonstrate the generation of pure white light with quantum yield of similar to 30%, color rendering index up to 95, and color temperature of 5500 K These results provide a guideline for the design of a new class of hybrid white-light-emitting nanophosphors and other multifunctional nanostructures based on transparent metal oxides.