Using mobile services for e-government opens a new way of interaction between governments, citizens and businesses as well as within the public administration. However, governments face different drivers and inhibitors in their adoption behaviour. In this paper we investigate the question why public sector organizations differ in their adoption of mobile government innovations. Based on 12 in-depth interviews with municipal IT decision makers, we apply grounded theory and content analysis to derive a framework for drivers and inhibitors of m-government adoption. Further, we utilize this framework to analyze four cases in detail and identify the contextual differences in such municipalities. Finally, we isolate the effects in the way IT is governed and derive the concept of transformational IT governance to explain the differences in municipal m-government adoption.