Vietcombank sold the dollar at VND24,490, down 0.29% from Thursday.
The State Bank of Vietnam maintained its reference rate at VND24,089.
The dollar was stable at VND24,450 on the black market.
It has increased by 3.20% against the dong since the beginning of the year.
Globally, the dollar held off a 10-month high on Friday as markets headed into the end of the quarter, giving the yen slightly more breathing room at the end of the week amid intervention concerns, Reuters reported.
The euro largely held its ground after rebounding overnight, but was still not far from its January low of $1.0482, which if broken would be the lowest since December.
The dollar index, which tracks the currency against six other majors, was mostly flat in the Asian morning, on track for an 11th straight week of gains, after dipping as low as 106.020 overnight.