Unofficial exchange points sold the greenback at VND24,550, up 0.41% from Sunday.
Vietcombank kept the greenback unchanged at VND24,460.
The State Bank of Vietnam lowered its reference rate by 0.12% to VND24,059.
The dollar has increased over the dongn by 3.08% since the beginning of the year.
Globally the dollar kicked off the last quarter of the year on the front foot on Monday as the prospect of higher-for-longer U.S. rates provided solid support, pushing the yen to an 11-month low, Reuters reported.
Currency moves were subdued in early Asia trade with parts of Australia out for a holiday and China away for its Golden Week, though analysts said a narrowly-averted U.S. government shutdown could bring some relief to markets.
The yen slid to a roughly 11-month low of 149.74 per dollar, as the Japanese currency continued its slow-but-steady decline toward the 150 mark, a level which some see as a line in the sand that would spur Japanese authorities to intervene in the currency market as they did last year.
"Fear of intervention by the BOJ above the 146 level has come and gone and the currency is now above 148 to the dollar and the BOJ remains absent from currency markets," said Olivier d'Assier, Axioma's head of applied research for APAC.