A quantum dot device including a first electrode and a second electrode each having a surface opposite the other, a quantum dot layer disposed between the first electrode and the second electrode, an electron transport layer disposed between the quantum dot layer and the second electrode and including first inorganic nanoparticles and a first organic material, and an electron injection layer disposed between the electron transport layer and the second electrode and including second inorganic nanoparticles and a second organic material, wherein a ratio by weight of an amount of the second organic material to a total amount of the second inorganic nanoparticles and the second organic material in the electron injection layer is less than a ratio by weight of an amount of the first organic material to a total amount of the first inorganic nanoparticles and the first organic material in the electron transport layer. An electronic device including the quantum dot device.