This study develops and tests a theoretical model to investigate the role of Green IT internal management within organisations. Specifically, this model explains the antecedents and the outcomes of Green IT Internal Management (GITIM). The hypotheses were tested using survey data from 133 Malaysian IT companies. Using Partial least Square (PLS) of structural equation model, the measurement model is accessed followed by structural model assessment. First, the result shows that GITIM can be constructed as formative second order construct constitutes of sourcing, operation and disposal dimensions. Second, the top management support in environmental issues does not have positive affect on GITIM. Rather, the knowledge stock and IT business experience have positive affect on GITIM. Third, GITIM is confirmed to positively affect competitive advantage; both cost and differentiation advantage. This study suggests that information system resources, which are known to be important for innovation process, also contribute to GITIM and in turn lead to competitive advantage.