It surged by 0.64% from Thursday to VND25,210 on the black market.
Vietcombank sold the dollar at VND24,920, the same price as the previous day.
The State Bank of Vietnam hiked its reference rate by 0.07% to VND24,133.
Since the beginning of the year, the greenback has increased by 2.05% against the dong.
Globally, the dollar hovered near a six-week high on Friday ahead of a payrolls report that could decide the path of U.S. interest rates, while the yen headed for its weakest weekly performance since 2016, hit by uncertainty over Japan's monetary policy, Reuters reported.
The dollar was also boosted by safe-haven demand as investors weighed widening Middle East tensions and their impact on the global economy.
The dollar index, which measures the U.S. unit against six peers, was last at 101.90, not far from a six-week high of 102.09 touched on Thursday. The index is up nearly 1.5%, for the week, its strongest such performance since April.
The euro was steady at $1.1034, having dropped 1.18% this week. The yen was 0.3% higher, at 146.43.