A semiconductor device may include a substrate, a first nanowire, a gate electrode, a first gate spacer, a second gate spacer, a source/drain and a spacer connector. The first nanowire may be extended in a first direction and spaced apart from the substrate. The gate electrode may surround a periphery of the first nanowire, and extend in a second direction intersecting the first direction, and include first and second sidewalls opposite to each other. The first gate spacer may be formed on the first sidewall of the gate electrode. The first nanowire may pass through the first gate spacer. The second gate spacer may be formed on the second sidewall of the gate electrode. The first nanowire may pass through the second gate spacer. The source/drain may be disposed on at least one side of the gate electrode and connected with the first nanowire. The spacer connector may be disposed between the first nanowire and the substrate. The spacer connector may connect the first gate spacer and the second gate spacer to each other.