Following a successful run in the recent second round of the 2020 AFC Women's Olympic Qualifying Tournament, Vietnam added 21 points to have 1,659 points to retain their sixth place in Asia.
Vietnam have been 35th in the world since last December.
Meanwhile, Thailand lost 42 points to drop to the 39th position with 1,616 points.
Behind Vietnam and Thailand in Southeast Asia are Myanmar with 1,521 points (world No 46), followed by the Philippines, Malaysia, Indonesia and Singapore.
The US top the world rankings after winning the 2019 FIFA Women's World Cup, followed by Germany and the Netherlands, the World Cup runners up.