A semiconductor light emitting device may include: a first conductivity-type semiconductor layer; an active layer disposed on the first conductivity-type semiconductor layer and including a plurality of quantum barrier layers and a plurality of quantum well layers which are alternately stacked; and a second conductivity-type semiconductor layer disposed on the active layer. A quantum barrier layer closest to the second conductivity-type semiconductor layer, among the plurality of quantum barrier layers, may include a first undoped region and a first doped region disposed on the first undoped region and having a thickness greater than or equal to that of the first undoped region. Each of the first undoped region and the first doped region may include a plurality of first unit layers having different energy band gaps, and at least one hole accumulation region.