A quantum dot, a quantum dot-polymer composite, and an electronic device including the same. The quantum dot includes a core including a first semiconductor nanocrystal; a first shell including a second semiconductor nanocrystal including a Group III-VI compound on the core; and a second shell including a third semiconductor nanocrystal having a composition different from that of the second semiconductor nanocrystal on the first shell; wherein one of the first semiconductor nanocrystal and the third semiconductor nanocrystal includes a Group III-V compound.