In the first five months, 176,681 vehicles were sold, up 39 percent year-on-year, according to data from the Vietnam Automobile Manufacturers Association (VAMA).
Passenger cars accounted for over 79 percent, and commercial vehicles and special-purpose vehicles for the rest.
Truong Hai Auto Corporation (Thaco) reported a 51-percent rise in sales to 66,414 units, and continued to lead the industry.
Toyota was second with 37,906 units, up 57 percent.
It was followed by Honda, Mitsubishi and Visuco (Suzuki), all of which saw sales rise in double-digits.
Ford came in sixth as sales declined by 24 percent to 7,663 units.
Last year, auto sales had dropped 3 percent to 383,444 units.