Disclosed are a light emitting device, a method for manufacturing the same, a light emitting device package, and a lighting system. The light emitting device includes a first conductive semiconductor layer, an active layer comprising a well layer and a barrier layer on the first conductive layer, and a second conductive semiconductor layer on the active layer. The well layer includes a first well layer closest to the first conductive semiconductor layer and having a first energy bandgap, a third well layer closest to the second conductive semiconductor layer and having a third energy bandgap, and a second well layer interposed between the first and third well layers and having a second energy bandgap. The third energy bandgap of the third well layer is greater than the second energy bandgap of the second well layer.