In spite of an Enterprise Systems Implementation Methodology's (ESIM's) potential and significance for Enterprise Systems implementation, little attention has been paid to its evolution in ES literature. Moreover, current studies reveal contradictory findings and provide a fragmented understanding. The purpose of this paper is to provide a framework underpinned by a morphogenetic approach for explaining how ESIM evolves by adaptation through reflexivity. Our qualitative study resulted in a richer description of ESIM contents differentiated by adaptation strategies through reflexivity. Four theoretically and empirically informed ESIM adaptation strategies, i.e. reorienting, embedding, aligning and connecting, with related conditions and effects are suggested. This study retains valuable insights of prior works in Information Systems Development (ISD) research, since ESIM might be regarded as one of the latest interventions undertaken in an attempt to improve the quality of an ES product and the productivity and quality of an implementation process.