A semiconductor device includes first and second active patterns, a field insulating film between the first and second active patterns, a first gate structure intersecting the first active pattern and including a first gate electrode and a first gate spacer, a second gate structure intersecting the second active pattern and including a second gate electrode and a second gate spacer, a gate separation structure on the field insulating film between the first and second gate structures, the gate separation structure including a gate separation filling film on a gate separation liner, and a connecting spacer between the gate separation structure and the field insulating film, the connecting spacer protruding from a top surface of the field insulating film, and the gate separation liner contacting the connecting spacer and extending along a top surface and sidewalls of the connecting spacer and along the top surface of the field insulating film.