This paper investigated the relationship between trade openness and ? ? ? emissions in Vietnam, using data from 1986 to 2014. We examined the consistency of the environmental Kuznets curve hypothesis and the Pollution Heaven hypothesis as applied to Vietnam. In 1986, the Vietnamese government began to launch free-market economic reforms. Since then, the economy of Vietnam has experienced breakthrough innovation in trade openness. On the other hand, Vietnam has witnessed a growing level of ? ? ? emissions. Our results showed that the relationship between ? ? ? emissions and per capita income is an inverted U-shape, consistent with the environmental Kuznets curve hypothesis. We also found that the Pollution Heaven hypothesis is supported in that energy use and international trade contribute to air pollution, but becoming a member of WTO has a positive effect on the Vietnamese environment.