Thai shares rose to a near eight-week closing high on Thursday after gains in the energy and financial sectors.
Vietnam and Malaysia shares dropped but other Southeast Asian markets were in the green on the Federal Reserve's dovish outlook.
The Fed kept rates at 2.25 % to 2.5 % on Wednesday as widely expected, which are well below historical averages.
The US central bank also discarded its promises of "further gradual increases" in interest rates, and said it would be "patient" before making any further moves amid signs of global economic slowdown and a damaging trade war with China.
Rising US borrowing costs in 2018 had led to massive capital flight from emerging markets, prompting regional central banks to hike rates to reduce the rate differential and combat a stronger US dollar.
"Markets clearly like the newly dovish Fed, which had exceeded expectations for dovishness in the midst of a positive output gap and tight labour market," Mizuho Bank said in a client note.
The Stock Exchange of Thailand index added 9.13 points or 0.56% to 1,641.72, in turnover worth 57 billion baht.
Kasikornbank Plc topped the most active stock. KBANK shares jumped 7 baht or 3.63% to 200 baht, Bangkok Bank shares gained 4 baht or 1.90% to 215 baht and Siam Commercial Bank shares closed at 133 baht, up 2 baht or 1.53%.
PTT Plc added 25 satang or 0.52% to 48.50 baht and PTT Global Chemical Plc ended 50 satang or 0.74% higher to 68 baht.
Indonesian shares jumped 1.1%, boosted by financial and industrial stocks. The index rose 5.5% in January in its third straight monthly gain.
Bank Central Asia and Unilever Indonesia gained about 2% and 1.9%, respectively.
An index of the country's top 45 liquid stocks climbed 1.5% to its highest since April 2018.
Philippine shares closed 0.3% higher after gaining as much as 1.5% earlier in the session.
The benchmark stock index pared its gains after the central bank said January annual inflation is likely to settle within a range of 4.3% to 5.1%, above its target of 2-4% for 2019.
Surging inflation had dented consumption and put pressure on the peso in 2018, prompting Bangko Sentral ng Pilipinas to hike its benchmark rate five times.
The Philippine stock index added 7.3% in January, in its sharpest monthly gain since March 2016.
Vietnam shares ended 0.6% lower, while Malaysian shares retreated from early gains to close flat.