China and the Association of Southeast Asian Nations (ASEAN), as the engine of world economic development, are facing tremendous challenges concerning the balance between economic growth and low-carbon development. Nevertheless, previous studies on the relationship between economic growth and carbon emissions have seldom been contextualized in this region. The paper analyses the decoupling elasticity between carbon dioxide (CO2), the gross domestic product (GDP) and energy consumption in China and the ASEAN countries over the period 1990–2014. Based on the Log-Mean Divisia Index (LMDI), it explores the effect of four factors on the total changes in CO2 emissions, namely the carbon density effect, energy intensity effect, economic effect in terms of per capita GDP and population effect. The study shows that the economic effect in terms of per capita GDP is the dominant driving force for the increase in CO2 emissions. The carbon density and population effects also play a role in this regard. Energy intensity has contributed significantly to the decrease in CO2 emissions in most of the examined countries. To decouple economic growth from environmental pressure, energy policies in China and the ASEAN countries need to scale up the share of renewable energy, increase the efficiency of energy use and implement green development as long-term targets in the region.