a light-emitting device including: a photoluminescent layer that contains a photoluminescent material and emits light including first light having a wavelength λa in air; and a light-transmissive layer located on or near the photoluminescent layer. At least one periodic structure is defined on at least one of the photoluminescent layer and the light-transmissive layer. The at least one periodic structure has projections or recesses or both. A distance Dint between two adjacent projections or two adjacent recesses and a refractive index nwav-a of the photoluminescent layer for the first light satisfy λa/nwav-a
