Unofficial exchange points sold the dollar at VND23,590, up 0.13% from Friday.
The greenback remained stable at most banks.
Vietcombank maintained the rate at VND23,620.
Eximbank sold the greenback at VND23,580, and Techcombank VND23,621.
The State Bank of Vietnam kept its reference rate unchanged at VND23,606.
The dollar has fallen against the dong by 0.46% since the beginning of the year.