Vietcombank sold the greenback at VND25,720, up 0.04% from the weekend. The dollar slipped 0.08% to VND25,800 on the black market.
The State Bank of Vietnam raised its reference rate by 0.06% to VND24,794.
Globally, the U.S. dollar hovered close to a five-month low against its major peers on Monday, pressured by President Donald Trump's erratic trade policies and a run of soft macroeconomic data, Reuters reported.
The dollar index, which measures the currency against the euro, yen and four other counterparts, was little changed at 103.71 early in the Asian morning, less than 0.5% away from a five-month trough of 103.21 reached last Tuesday.
The index is currently down almost 6% from the more than two-year peak of 110.17 touched in mid-January, as optimism that Trump's presidency would spur growth turned into worries that his trade policies could trigger recession.
The euro stood not far from a five-month peak after German parties on Friday agreed on a fiscal deal that could boost defense spending and revive growth in Europe's largest economy.
The euro was fetching $1.0881, slightly off the $1.0947 level it hit last Tuesday for the first time since Oct. 11.
The dollar was little changed at 148.70 yen, not straying far from last Tuesday's trough at 146.545, the weakest level since Oct. 4. Sterling slipped 0.08% to $1.2927.