The index closed 18.31 points lower after losing 14.1 points on Friday.
Trading on the Ho Chi Minh Stock Exchange (HoSE) increased by 42.49% to VND9.33 trillion ($391.85 million).
The VN-30 basket, comprising the 30 largest capped stocks, saw 27 tickers dropped.
MSN of conglomerate Masan Group plunged 7%, followed by NVL of property developer Novaland Group with a 5.7% decline.
SSI of leading brokerage SSI Securities Corporation dropped 3.9% and MWG of electronics retail chain Mobile World lost 3.8%.
HDB of HDBank fell 3.4%.
Only two blue chips gained. VJC of budget airline Vietjet rose 2.4% and VNM of dairy giant Vinamilk closed 0.7% higher.
Foreign investors were net sellers to the tune of VND658.16 billion, mainly selling VHM of property giant Vinhomes and SSi.
The HNX-Index at the Hanoi Stock Exchange, where mid and small caps list, was down 1.95% while the UPCoM-Index at the Unlisted Public Companies Market was down by 1.15%.