A blue organic light emitting device including a first electrode, a second electrode facing the first electrode, a first charge generating layer disposed between the first electrode and the second electrode, a first emission layer disposed between the first electrode and the first charge generating layer and emitting first blue light having a first wavelength region, and a second emission layer disposed between the first charge generating layer and the second electrode and emitting second blue light having a second wavelength region different from the first wavelength region. The blue organic light emitting device finally emits blue light.