The environmental tax on the popular gasoline RON95 will be reduced from VND4,000 ($0.17) to VND2,000 per liter.
The tax cut will apply to gasoline and diesel starting April 1 and will last until the end of the year.
The tax cut demonstrates the state's support for the people and businesses as the economy recovers from Covid-19 impacts, said Nguyen Phu Cuong, head of the National Assembly Finance and Budget Committee.
However, some lawmakers disagreed with the cut, saying it would appear that Vietnam was not making serious efforts to reduce harmful impacts on the environment.
They said that instead of the environmental tax, it was the special consumption tax that should have been cut to stabilize gasoline prices.
Several lawmakers also suggested that the government includes gasoline, not just cash, in its stabilization fund.
Gasoline prices in Vietnam reached a new peak on March 11 before declining slightly to VND29,190 per liter this week.
It has risen over 25 percent so far this year.