This first OECD Investment Policy Review of Southeast Asia builds on national reviews of seven countries in Southeast Asia. It looks at common challenges across the region and at the interplay between regional initiatives and national reforms. The regional Review allows for a discussion of more thematic issues than are usually considered in the country-level reviews, including the possible role of regional initiatives in driving reform. It includes the following chapters: trends in foreign direct investment (FDI) in Southeast Asia, particularly in services; the unfinished agenda of FDI liberalisation in the region; the role of liberalisation in boosting both service sector and overall productivity in ASEAN; the evolution of investment protection in Southeast Asia; towards a smarter use of tax incentives in the region; and at how promoting and enabling responsible business conduct can help to maximise the development impact of investment.