In this paper we develop an Enterprise Systems Implementation Methodology in Action framework. The framework is grounded in contemporary views on methodology in action (theoretical grounding) and enhanced by an empirical study (empirical grounding). The notion of Implementation Methodology in Action, as articulated in this paper, integrates two complementary views that conceptualise a methodology in terms of 1) a technology focusing on a formalised aspect, i.e. content as prescribed by designers, and 2) a structural view focusing on situational aspects including implementers, implementation context, Enterprise Systems Software and other individuals participating in the implementation project. The purpose of the framework is to integrate existing methodology views in order to contribute to a better understanding of Enterprise Systems implementation methodology. The integrated methodology concept is understood in terms of formalised and situational elements. These elements exert a significant influence on the characteristics and effectiveness of methodology use and implementers’ actions, which may explain differences in the outcomes of the Enterprise Systems implementation process. The results from this research also helps participants in Enterprise Systems projects to become aware of the elements which may influence the actions of the users working with implementation methodologies as well as the reasons for these actions in the Enterprise Systems implementation.