A light emitting device including a first light emitting stack, a second light emitting stack disposed under the first light emitting stack, a third light emitting stack disposed under the second light emitting stack, first, second, third, and fourth connection electrodes disposed over the first light emitting stack, and electrically connected to the first, second, and third light emitting stacks, and bonding metal layers disposed on upper surfaces of the first, second, third, and fourth connection electrodes, in which each of the first, second, third, and fourth connection electrodes includes a groove on an upper surface thereof, and the bonding metal layers cover the grooves of the first, second, third, and fourth connection electrodes, respectively.