A semiconductor light emitting device according to an embodiment includes a stacked body. The stacked body includes a first semiconductor layer of a first conductivity type, a light emitting layer is provided on the first semiconductor layer, and a second semiconductor layer of a second conductivity type provided on the light emitting layer. The stacked body includes a first protrusion on an upper surface of the stacked body. The first protrusion protrudes in a first direction from the first semiconductor layer to the light emitting layer. Length of the first protrusion in a second direction perpendicular to the first direction decreases toward the first direction. The first protrusion includes a first portion and a second portion. The first portion has a first side surface inclined with respect to the first direction. The second portion is provided below the first portion and having a second side surface inclined with respect to the first direction. The second side surface is curved so as to be convex downward.