Provided are a light emitting device and an optical coupling module. The device includes a substrate, a light emitting part provided to the substrate, and a reflecting part provided to a lower surface of the substrate. The light emitting part includes an active pattern disposed on the substrate, an upper mirror provided to an upper portion of the active pattern, and a lower mirror provided to a lower portion of the active pattern. The light emitting part may emit light normal to the substrate, and the reflecting part may reflect the emitted light to a side surface of the substrate.