The results indicate that the economic growth, energy consumption, financial development and trade openness positively influence the CO2 emissions, whereas foreign direct investment has a negative impact in the short term. Coefficient of joining ASEAN is not statistically significant. The findings of this study also support the validity of EKC and PHH in the Vietnamese economy. | Online ISSN 2345-0037. ORGANIZATIONS AND MARKETS IN EMERGING ECONOMIES, 2017, VOL. 8, No. 2(16) Factors Affecting CO2 Emission in Vietnam: A Panel Data Analysis Le Trung Thanh* University of Economics and Business, Vietnam National University Nguyen Duc Khuong University of Economics and Business, Vietnam National University Abstract. The purpose of this study is to investigate the major factors in the process of economic growth that influence the carbon dioxide (CO2) emission in Vietnam. An Autoregressive Distributed Lag (ARDL) model was used to evaluate the impact based on Environmental Kuznets curve (EKC) and Pollution haven hypothesis (PHH) in 1990–2011. The results indicate that the economic growth, energy consumption, financial development and trade openness positively influence the CO2 emissions, whereas foreign direct investment has a negative impact in the short term. Coefficient of joining ASEAN is not statistically significant. The findings of this study also support the validity of EKC and PHH in the Vietnamese economy. Therefore, it is important to use green energy, examine requirements for foreign investment and adopt trade-related measures and policies to increase environmental protection. Key words: Environmental Kuznets Curve hypothesis, pollution haven hypothesis, economic growth, CO2 emission 1. Introduction Vietnam has been considered as one of the countries that enjoy the fastest economic growth rate of around 6 percent between 2010 and 2015 (Statistical yearbook of Vietnam, 2016). However, like other countries in the world, this growth is usually accompanied by the significant increase in energy consumption and environmental problems, for example, CO2 emissions (Balibey, 2015; Linh & Lin, 2014). According to Vietnam development report (2011), the level of emissions per capita in Vietnam remained at about two metric tons of CO2, ranking 111th in the world and, it is expected to rise dramatically in the coming time ( Jan, 2011). Vietnam is