It closed 13.14 points lower after losing 3.2 points on Thursday.
Trading on the Ho Chi Minh Stock Exchange (HoSE), on which the index is based, rose 5.6% to VND25.193 trillion ($1.01 billion).
The VN30 basket, comprising the 30 largest capped stocks, saw 26 tickers fell.
GVR of Vietnam Rubber Group saw the biggest decline, plumetting 4.8%, followed by VRE of retail real estate arm Vincom Retail with a 2.4% drop and SSI of brokerage SSI Securities Corporation, down 2.3%.
Only two blue chips gained, including VPB of private lender VPBank with a 0.8% growth and MWG of electronics retail chain Mobile World, which went up 0.6%.
Foreign investors were net buyers to the tune of VND25.83 billion, mainly buying NVL of property developer Novaland and MWG of Mobile World.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, dropped 1.14% while the UPCoM-Index for the Unlisted Public Companies Market fell 0.4%.