An electroluminescent device and a display device including the same are provided. The electroluminescent device includes a first electrode and a second electrode facing each other; an emission layer disposed between the first electrode and the second electrode and including at least two light emitting particles; a hole transport layer disposed between the first electrode and the emission layer; and an electron transport layer disposed between the emission layer and the second electrode and including at least two different organic semiconductor compounds, wherein a first root-mean surface roughness of a surface of the electron transport layer obtained using a laser interferometer is in a range from about 0.5 nanometers to about 3 nanometers.