Vietcombank sold the dollar at VND23,855, down 0.02% from Sunday.
The State Bank of Vietnam kept its reference rate unchanged at VND23,758.
The dollar was sold 0.08% higher at VND23,720 on the black market.
It has gained over the dong by 0.53% since the beginning of the year.
Globally the yen fell on Monday, extending losses from a volatile session at the end of last week after the Bank of Japan (BOJ) loosened its grip on interest rates, but was still on track to reverse three consecutive months of declines, Reuters reported.
The yen was about 0.3% lower at 141.57 per dollar, but was headed to end July with a roughly 2% gain, its first monthly rise since March.
On Friday, the yen went into a tailspin as traders tried to determine the implications of the BOJ's move to maintain ultra-low rates while making its bond yield curve control (YCC) policy more flexible and loosening its defence of a long-term rate cap.
The dollar eventually ended the Friday session with a 1.2% gain against the Japanese currency, though that was after it had slid 1% to a session-low of 138.05 yen.