The index closed 9.59 points lower after gaining 5.85 points in the previous session.
Trading on the Ho Chi Minh Stock Exchange decreased by 18% to VND14.79 trillion (US$585 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 27 tickers fell.
POW of electricity producer Petrovietnam Power Corporation fell 2.9%, and MSN of conglomerate Masan Group closed 2.7% lower.
ACB of Asia Commercial Bank dropped 2% and GVR of Vietnam Rubber Group declined by 1.8%.
Three blue chips gained, including SSB of SeABank with a 2.4% rise and BVH of insurance company Bao Viet Holdings, up 1.4%.
Foreign investors were net sellers to the tune of VND302 billion, mainly selling MWG of electronics retail chain Mobile World and MSN.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 0.42%, while the UPCoM-Index for the Unlisted Public Companies Market went down 0.45%.
Asian markets started what could be a momentous month warily, with shares mostly lower and Treasury yields near three-month highs on Friday, while investors wait for U.S. jobs data, although a rate cut next week is largely baked in, Reuters reported.
Tokyo's Nikkei fell 2.6% as a stronger yen clouded the outlook for Japanese exporters. The dollar rose 0.3% to 152.46 yen on Friday.
MSCI's broadest index of Asia-Pacific shares outside Japan, on the other hand, rose 0.2% thanks to gains in Chinese stocks, but was still down 1.3% for the week.