Sweden is divided into 290 municipalities. The municipalities are responsible for many services that generates significant amount of CO2 emissions. For example; energy, waste management andstreetlights. This emission can potentially be reduced by using Green IT - smart IT solutions that optimise the processes or reduces the energy needed. One good example is adaptive street lighting that utilize sensors to identify when someone is nearby and light needs to be on. The utilization of Green IT differs a lot between the municipalities. Why is this the case? Municipalities are not competing with each other, and it seems like low hanging fruit to just “copypaste” a successful Green IT solution from one municipality to another. The purpose of this study was to investigate the mechanism around diffusion of Green IT innovations related to Swedish municipalities. We applied a mixed method approach based on interviews and a questionnaire. Managers within the municipalities served as the source of empirical data. We found that there are several different types of factors that probably has an impact on the diffusion of Green IT innovation within municipalities and we investigated their relative importance. A high-level explanation of what factors that are considered to enable the diffusion of Green IT innovation is: Firstly, there need to be a willingness to change, for example by applying a policy or target settings. Secondly, superior Green IT solutions need to be identified and here the best forum is networking with other municipalities. Then innovation needs to be transformed to fit the specific municipality, which calls for the organisation’s own innovation capabilities. To finally implement the Green IT solutions there need to be available resources within IT and change management skills to successfully implement them. This study was made with mixed method approach based on a relatively small dataset and without measuring the actual rate of diffusion. The recommendation for future research is to further develop and validate our construct by testing the correlation between the factors identified in this study and the actual rate of diffusion of Green IT innovations within Swedish municipalities.