The Defence Signals Directorate is Australia's SIGINT-collection agency. It operates monitoring facilities at Kojarena, near Gelaldton in Western Australia and at Shoal Bay, Northern Territory, which are believed to be part of the Echelon system. It may also play a role in Pine Gap.

Under the 1948 UKUSA agreement, DSD's intelligence is shared with the United States National Security Agency, the British Government Communications Headquarters, the Canadian Communications Security Establishment and the New Zealand Government Communications Security Bureau.

see also National Security Agency, espionage