Viet Nam dropped to 120th place in FIFA's June rankings, falling 22 steps, despite winning two friendly matches last month.
In Southeast Asia, the Vietnamese men remain the leader, followed by Thailand (135th) and the Philippines (152nd).
In Asia, Japan top the list at 20th place, followed by Australia, South Korea, Iran and Uzbekistan.
Spain still lead the world rankings after winning the EURO 2012 championship. The second and third places go to Germany and Uruguay, respectively.
The next FIFA rankings will be announced on August 8.
Viet Nam have been placed in the world's top 100 for the past seven months. — VNS