It went up 0.59% to VND25,700 on the black market.
Meanwhile, Vietcombank sold the dollar at VND24,810, down 0.12% from the previous day.
The State Bank of Vietnam (SBV) kept it reference rate steady at VND23,972.
The greenback has increased against the dong by 1.6% since the beginning of the year.
Globally, the yen strengthened against the dollar on Monday as signs the Bank of Japan will exit negative interest rates at its policy meeting next week contrasted with expectations for the Federal Reserve to cut rates in June, according to Reuters.
The greenback eased 0.17% to 146.82 yen, heading back toward the five-week low of 146.48 reached on Friday.
The dollar index was flat at 102.68, hovering not far from Friday's low of 102.33, a level not seen since Jan. 15.
The euro was little changed at $1.0944 after jumping as high as $1.0980 on Friday for the first time since Jan. 12.