The greenback declined by 1.31% to VND26,300 at unofficial exchange points.
Vietcombank kept its rate unchanged at VND26,387.
Globally the dollar gained on Friday after U.S. President Donald Trump praised economic adviser Kevin Hassett at a White House event and said he may want to keep him in his current role, prompting speculation he is less likely to be named as chair of the Federal Reserve, Reuters reported.
The dollar index, which measures the greenback against a basket of currencies including the yen and the euro, rose 0.06% to 99.41, with the euro down 0.1% at $1.1594. The index reached a six-week high of 99.49 on Thursday.
The U.S. currency has been boosted this week by data showing an improving U.S. labor market, which has pushed back expectations of further Federal Reserve rate cuts until June.