An in-line dust shutter formed as part an adapter. A hinged dust shutter assembly is secured to an adapter wall. A shutter plate covers an opening formed at either end of the adapter to prevent debris from entering the adapter and distorting the light signal between opposing fiber optic connectors. The shutter plate extends at angle alpha from a rotational axis. The shutter plate is biased closed by a bias spring place about a pin of the rotational axis.