Building off of the new institutional economics and e-commerce adoption literatures, we conduct a cross-country analysis assessing the impact and effect of national information ecology on global e-commerce adoption in the years of 2003 and 2007, respectively. We utilize a secondary dataset from the Global E-readiness Rankings of the Economist Intelligence Unit, which evaluated information environments and e-commerce adoption in major economies around the world. The results of the analysis indicate that at the infant stage of e-commerce, supportive government policies, effective legal environment and compatible socio-cultural infrastructure were powerful facilitators of e-commerce adoption. As e-commerce becomes more prevalent, supportive government policies and socio-cultural infrastructure foster e-commerce activities, while the effect of the legal environments becomes negligible. The study presents evidence that national information ecologies, shaped by various institutional environment factors, exert influence on a country’s e-commerce adoption at different stages of e-commerce development. It is one of the first cross-country studies on the relationship between national institutional environments and e-commerce adoption and the research findings have managerial and policy implications for global e-commerce development.