The question "Who joined NATO first?" is slightly ambiguous. A more precise phrasing would be: Which countries were the original founding members of NATO?
According to the provided reference, the founding member countries of NATO were:
- Belgium
- Canada
- Denmark
- France
- Iceland
- Italy
- Luxembourg
- The Netherlands
- Norway
- Portugal
- The United Kingdom
- The United States
Therefore, all of these countries joined NATO at the same time, making them the first members. It is not a sequential joining process among these original members. They were all founding members in 1949.
