Vietcombank sold the dollar at VND25,458, down 0.02% from Thursday.
The greenback slid 0.33% to VND25,825 on the black market.
The State Bank of Vietnam (SBV)'s reference rate was 0.02% lower at VND24,246.
Since the beginning of the year, the dollar has increased against the dong by 4.25%.
Globally, the U.S. dollar was hovering near three-week lows on Friday ahead of payrolls data that will likely influence the outlook for rates, Reuters reported.
It is up 0.9% for the week, its best weekly performance since mid-May and remains the strongest-performing major currency against the dollar this year with a gain of 1.2%.
The euro was little changed at $1.0816 as traders refrained from making major bets with France gearing up for the run-off election on Sunday.
The dollar index, which measures the U.S. currency against six rivals, was down 0.1% at 105.05, close to its lowest point since mid-June.
The yen was 0.16% higher, up for a second straight day - something that hasn't happened since the start of June. It last fetched $161.095 per dollar, crawling slowly away from the 38-year low of 161.96 on Wednesday.