This optical receptacle has a first optical surface, a reflection surface, a second optical surface, a light separation part, and a third optical surface. On the first optical surface, light from a photoelectric conversion element is incident. The reflection surface reflects the light incident on the first optical surface. The second optical surface allows the light reflected by the reflection surface to be emitted toward an end surface of an optical transmission body. The light separation part separates the light reflected by the reflection surface, into monitor light and signal light. The third optical surface allows the monitor light to be emitted toward a detection element. The light separation part includes divided reflection surfaces and divided transmission surfaces. At least one of the divided transmission surfaces includes one or more widened portions each having a width larger than those of the other divided transmission surfaces.