A semiconductor light emitting device includes first conductivity type and second conductivity type semiconductor layers, an active layer disposed between the semiconductor layers and having a structure in which one or more quantum well layers and one or more quantum barrier layers are alternately disposed An electron blocking layer is disposed between the active layer and the second conductivity type semiconductor layer. A capping layer is disposed between the active layer and the electron blocking layer and blocking a dopant element from being injected into the active layer from the second conductivity type semiconductor layer.