A light emitting device includes: a first electrode and a second electrode facing each other, an emissive layer disposed between the first electrode and the second electrode and including a quantum dot, an electron auxiliary layer disposed between the emissive layer and the second electrode and including a plurality of nanoparticles, and a polymer layer between a portion of the second electrode and the electron auxiliary layer, wherein the nanoparticles include a metal oxide including zinc, wherein the second electrode has a first surface facing a surface of the electron auxiliary layer and a second surface opposite to the first surface, and the polymer layer is disposed on a portion of the second surface and a portion of the surface of the electron auxiliary layer, and wherein the polymer layer includes a polymerization product of a thiol compound and an unsaturated compound having at least two carbon-carbon unsaturated bonds.