Lawmakers have unanimously voted to permanently keep corporate income tax at 20% of net profits following temporary cuts to that level over past few years.
The National Legislative Assembly on Friday voted 160 in favour of the amendment bill to the Tax Code.
The 20% rate aims to improve the competitiveness of Thai companies and partnerships.
Deputy Finance Minister Wisudhi Srisuphan said the change would help stimulate the economy and attract inflows.
"The lower rate won't affect overall revenue collection. We are restructuring the tax regime to plug some loopholes and expand the tax base," he said.
Mr Wisudhi added given the fragile economy, a tax hike was a risky move as it might further weaken the economy.
"The government therefore chose to revamp tax collection methods instead," he said.