As the Southeast Asian countries heavily rely on coal and natural gas for electricity generation, the governments promote renewable energy as an essential component of sustainable development, energy security, cleaner air, and reduced carbon emissions. Solar photovoltaic is one of the abundant and potential renewable energy sources across those countries. Even though five Southeast Asian countries (Indonesia, Malaysia, Philippines, Thailand and Vietnam) have implemented the FIT policy, the solar PV capacity has significantly varied among these countries, which prompt us to analyse the FIT policy structure, FIT efficiency, drivers, and barriers to penetration solar PV. The results showed that initially, the FIT efficiency is high, and then there is a decreasing FIT efficiency trend found in five Southeast Asian countries. Thailand exhibits relatively stable performance, and Indonesia's FIT performance is unstable, while Vietnam has recently seen a rocketed investment. The vital policy implications would focus on the appropriate FIT policy design along with trade policy and techno-industrial development to penetrate solar PV.