The Stock Exchange of Thailand index ended at their highest in nearly three weeks, while other Southeast Asian stock markets closed higher on Monday, in line with broader Asian peers.
Risk sentiment improved following US Federal Reserve Chairman Jerome Powell's comments on gradual interest rate hikes.
Powell said gradual rate hikes were the best way to protect the US economy and signalled more hikes were coming despite President Donald Trump's criticism of higher borrowing costs.
"Powell's comments, somewhat, supported risk sentiment, as the Fed is unlikely to tighten faster than planned despite inflation moving up to near 2%," Mizuho Bank said.
MSCI's broadest index of Asia-Pacific shares outside Japan was up 1.2%.
The SET index gained 13.42 points or 0.79% to close at 1,717.24, in turnover worth 47 billion baht.
The index ended at their highest in nearly three weeks, with oil and gas producer PTT Plc closing 0.5% higher, while Bank of Ayudhya finished 2.5% firmer.
Thailand is set to release manufacturing data for July on Tuesday. Annual manufacturing output in July is expected to have risen at a slightly slower pace than in the previous month, a Reuters poll showed.
Boosted by materials and telecommunication sectors, the Indonesian bourse marked its highest close in more than two weeks.
Telekomunikasi Indonesia closed over 5% firmer, while diversified conglomerate Astra International added 2.7% to the benchmark.
An index of the country's 45 most liquid stocks was up 1.4%.
Singapore shares closed higher, led by financials and industrials. Shares of Jardine Matheson Holdings and Oversea-Chinese Banking Corp ended around 1% firmer.
Malaysian shares edged higher to a three-month closing high, buoyed by financials and materials.
Malayan Banking and Petronas Chemicals Group ended up 1.22% and 1.4%, respectively.
Philippine financial markets were closed for a holiday.
