Vietcombank sold the dollar at VND24,450, down 0.20% from Monday.
The State Bank of Vietnam let its reference rate slide by 0.21% to VND24,014.
The greenback fell 0.08% to VND24,600 on the black market.
It has increased against the dong by 3.03% since the beginning of the year.
Globally the dollar was steady on Tuesday, holding overnight gains as investors took a breather from a risk rally, while the Australian currency drifted lower ahead of a central bank interest rates decision later in the day.
The Australian dollar was 0.23% lower at $0.6474, but remained close to the three-month peak of $0.6523 touched on Monday.
The euro was down 0.07% to $1.0708, easing away from the eight-week peak of $1.0756 hit on Monday. Sterling was last at $1.2336, down 0.04% on the day, just shy of the seven-week high of $1.2428 it hit on Monday.
Against a basket of currencies, the dollar index rose 0.057% to 105.32, having climbed 0.2% on Monday, but remained not far off a nearly two-month low of 104.84 touched on Monday.