The market and popularity of e-cigarettes are growing rapidly worldwide.However,the research and regulation of this novel product have lagged behind.In this paper,we review and compare the regulatory mechanisms regarding e-cigarettes among ten Association of Southeast Asian Nations (ASEAN) member states.Our findings demonstrate a continuum of the legal regulations of e-cigarettes in Southeast Asia:on the one end,countries such as Brunei,Cambodia,Thailand,and Singapore have prohibited the importation and sale of e-cigarettes with existing tobacco control laws or specific regulations;on the other end,countries such as Myanmar and Vietnam have almost no legal restrictions on e-cigarettes whatsoever.This overview of national regulations will not only clarify the legal status of e-cigarettes in Southeast Asia but also provide some informing lessons for the tobacco control efforts in this region.