The current study attempts to understand the relationships among Environmental Quality (EQ), Human Development (HD) and political and governance regimes in a cross-country framework through secondary data analysis. The underlying hypothesis is that in addition to income, as reflected from the literature on the Environmental Kuznets Curve hypothesis, several other factors, including socioeconomic (e.g. human development and corruption) and sociopolitical (e.g. ability to exercise democratic rights) factors, may influence environmental policy-making, and thereby environmental sustainability, in a country. The EQ (i.e. environmental sustainability) of the countries in the current study is denoted by their Environmental Performance Index (2008). Human development is represented by Human Development Index (2007). Democracy Index (2008) and Corruption Perceptions Index (2008) are considered as proxies for political transparency in a country and its susceptibility to rent-seeking activities, respectively. The cross-country empirical findings confirm the closer association between the socioeconomic and sociopolitical factors and sustainable development. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.