The popular fuel RON95 dropped 1.20% to VND20,600 ($0.81) per liter.
Biofuel E5 RON92 fell 1.45% to VND19,450.
Diesel declined by 1.80% to VND18,570.
On Wednesday OPEC cut its oil demand growth forecasts for this year and next for a fourth consecutive month as it belatedly recognized a slowdown in top consumer China, Bloomberg reported.
Apart from OPEC's decision, regulators said that fuel prices in the last seven days were affected by strengthening U.S. dollar, and ongoing conflicts in the Middle East and between Russia and Ukraine.
Gasolines fell by 1.6-2.2% in the period, while oils dropped 2-3%.
RON95 is now priced at $84.1 per barrel, and diesel $88.6.