A light emitting diode includes a first light emitting cell and a second light emitting cell comprising an n-type semiconductor layer, and a p-type semiconductor layer, respectively; reflection structures contacting the p-type semiconductor layers; a first contact layer in ohmic contact with the n-type semiconductor layer of the first light emitting cell; a second contact layer in ohmic contact with the n-type semiconductor layer of the second light emitting cell and connected to the reflection structure on the first light emitting cell. An n-electrode pad is connected to the first contact layer; and a p-electrode pad is connected to the reflection structure on the second light emitting cell. The first light emitting cell and the second light emitting cell are isolated from each other, and their outer side surfaces are inclined steeper than the inner sides. Therefore, a forward voltage may be lowered and light output may be improved.