There is provided a semiconductor light-emitting device including a base layer formed of a first conductivity-type semiconductor material, and a plurality of light-emitting nanostructures disposed on the base layer to be spaced apart from each other, and including first conductivity-type semiconductor cores, active layers, and second conductivity-type semiconductor layers. The first conductivity-type semiconductor cores include rod layers extending upwardly from the base layer, and capping layers disposed on the rod layers. Heights of the rod layers are different in at least a portion of the plurality of light-emitting nanostructures, and heights of the capping layers are different in at least a portion of the plurality of light-emitting nanostructures.