Last updated: October 27, 2026. Reference guide, reviewed when the underlying official data changes.
The Five Eyes countries are the United States, the United Kingdom, Canada, Australia and New Zealand. They form an intelligence-sharing alliance built on the 1946 British-U.S. communications intelligence agreement, now known as UKUSA, according to the National Security Agency.
Five Eyes members and their signals agencies
| Country | Signals intelligence agency | Role in the founding papers |
|---|---|---|
| United States | National Security Agency (NSA) | Signatory, 1946 |
| United Kingdom | Government Communications Headquarters (GCHQ) | Signatory, 1946 |
| Canada | Communications Security Establishment (CSE) | Second Party |
| Australia | Australian Signals Directorate (ASD) | Second Party |
| New Zealand | Government Communications Security Bureau (GCSB) | Second Party |
New Zealand’s GCSB lists its Five Eyes partner agencies as the ASD, CSE, GCHQ and NSA; ASD and GCHQ describe their own missions. The NSA calls its four partners “Second Parties.” Canada’s government describes CSE as “a member of the Five Eyes intelligence alliance” with “long-standing cryptologic partnerships” with the other four, in its CSE briefing book.
Origins: from BRUSA to UKUSA
- World War II: the U.S. Army and Navy each built signals intelligence ties with Britain and with Canada, Australia and New Zealand.
- June 1943: agreements between the U.S. War Department, the U.S. Army and Britain’s Government Code and Cypher School covered “special intelligence.”
- March 5, 1946: the British-U.S. Communications Intelligence Agreement, then called BRUSA, was signed.
- 1946–1956: appendices set working rules between the two and arrangements with the other three partners.
The NSA has published the declassified agreement and appendices; Britain’s National Archives holds its copy.
What the alliance does today
Partners share signals intelligence and cyber security work. Canada says its priorities “are often aligned with Five Eyes partners, so sharing is extensive,” and that anyone who wants to use or spread a partner’s intelligence must ask the originating agency first. The five countries’ intelligence oversight bodies also meet in the Five Eyes Intelligence Oversight and Review Council, which the U.S. intelligence inspector general takes part in.
For every major service by country, see World intelligence agencies explained.
Frequently asked questions
Which countries are in the Five Eyes?
The United States, the United Kingdom, Canada, Australia and New Zealand.
When was the Five Eyes alliance formed?
Its founding document, the British-U.S. Communications Intelligence Agreement, was signed on March 5, 1946, building on wartime cooperation.
Is Five Eyes a treaty?
It rests on the UKUSA agreement and its appendices rather than a public treaty ratified by parliaments.
Is Germany or Japan in Five Eyes?
No. The alliance has five members only.
Related on Peter’s World
Sources
- National Security Agency: UKUSA Agreement release
- Government of Canada: Communications Security Establishment 101
Additional sources
- GCSB: About us (Five Eyes partnership)
- Australian Signals Directorate: About
- GCHQ: Mission overview
- UK National Archives: British-US Communication Intelligence Agreement (HW 80/4)
- ODNI: Five Eyes Intelligence Oversight and Review Council
By Peter. This guide was prepared with AI assistance and checked against the sources listed above.
