A light-emitting device and a lighting device each of which includes a plurality of light-emitting elements exhibiting light with different wavelengths are provided. The light-emitting device and the lighting device each have an element structure in which each of the light-emitting elements emits only light with a desired wavelength, and thus the light-emitting elements have favorable color purity. In the light-emitting element emitting light (λR) with the longest wavelength of the light with different wavelengths, the optical path length from a reflective electrode to a light-emitting layer (a light-emitting region) included in an EL layer is set to λR/4 and the optical path length from the reflective electrode to a semi-transmissive and semi-reflective electrode is set to λR/2.