It fell 0.55% to VND25,390 at unofficial exchange points.
Vietcombank maintained its rate at VND25,230.
The State Bank of Vietnam kept its reference rate unchanged at VND24,254 for the third day in a row.
The dollar has risen against the dong by 3.23% since the beginning of the year.
Globally the dollar fell against the yen on Friday, and was softer against other peers as traders took profits and investors sifted through economic data to gauge the Federal Reserve's appetite for interest-rate cuts, Reuters reported.
Disappointing U.S. housing numbers also kept pressure on the greenback, helping it shed some of the lift it got a day earlier from data showing inflation trending down and consumer resilience.
The dollar fell 1.04% against the Japanese yen to 147.75, having touched a two-week high of 149.40 in the prior session. Still, the yen looked on course for its biggest weekly decline since June after U.S. economic data eased fears of a recession and supported bets of gradual rate cuts.
The dollar index, which measures the greenback against six other major currencies, fell 0.48% to 102.54.