According to one embodiment, a semiconductor light emitting device includes a first layer of n-type and a second layer of p-type including a nitride semiconductor, a light emitting unit provided between the first and second layers, a first stacked structure provided between the first layer and the light emitting unit, and a second stacked structure provided between the first layer and the first stacked structure. The light emitting unit includes barrier layers and a well layer provided between the barrier layers. The first stacked structure includes third layers including a nitride semiconductor, and fourth layers stacked with the third layers and including GaInN. The fourth layers have a thinner thickness than the well layer. The second stacked structure includes fifth layers including a nitride semiconductor, and sixth layers stacked with the fifth layers and including GaInN. The sixth layers have a thinner thickness than the well layer.