Systems and methods for intrusion detection using selective masking are provided. Some methods can include receiving a first signal from an intrusion detection system indicative of a first number of individuals within a zone of a secured area, receiving a second signal from an access control system indicative of a second number of authorized persons within the secured area, receiving a third signal from an internal positioning system indicative of a respective location of each of the authorized persons within the secured area, and correlating the first signal, the second signal, and the third signal to determine whether an unauthorized person is within the zone.