The purpose of the paper is to discuss the phenomenon why some system dynamics projects fail to generate substantial impact in organizationsódespite the fact that they are based on an apparently valid system dynamics model and are conducted by experts in the field. The approach followed in the paper is a conceptual discussion, extended by a few short case studies. Findings are that the quality of the model and the expertise of the modeler are necessary, but not sufficient requirements for organizational impact. Further research should concentrate on the detailed analysis of additional requirements. Practical implications are an increased embedding of system dynamics projects in organizational intervention architectures. The originality of the paper lies in its focus and discussion of failed projects that are invaluable sources for insight generation.