Semiconductor devices are provided. The semiconductor devices may include a first interconnection structure and a second interconnection structure which are disposed on a semiconductor substrate. A contact structure may be disposed between the first and second interconnection structures. A first lower air spacer may be disposed between the first interconnection structure and the contact structure. A second lower air spacer may be disposed between the second interconnection structure and the contact structure to be spaced apart from the first lower air spacer. An upper air spacer may be disposed on side surfaces of the contact structure to be connected to the first and second interconnection structures.