A recent Gartner Research report found that environmental concerns are increasingly exercising the minds of business and IT executives. This is reflected in the growing interest in the adoption of environmentally responsible approaches to the deployment, operation and use of IT. However, for the majority of firms, issues of cost reduction and energy efficiency appear to predominate. This paper argues that whether it is an interest in Green IT or in cost reduction, the concerns of business and IT managers are modulated by regulative, normative, and cultural-cognitive influences in the institutional environment. The study therefore applies institutional theory to develop a series of theoretical propositions which specify the effect that such influences have in shaping environmental responsibility in organisations. Important as such a theoretical contribution may be, there are, however, the pressing practical imperatives of formulating Green IT strategies, achieving energy efficiencies, and reducing carbon footprints—thus, the study also contributes to a practical understanding of the complex institutional influences at play in shaping such imperatives