Attention to the subject of organizational effectiveness has been increasing in the last several years as popular management books have extolled management excellence, almost two million jobs have been lost due to poor U.S. competitiveness, and economic conditions have put pressure on organizations to become more accountable with their resources. However, despite its popularity, much confusion continues in the organizational literature regarding the definition, circumscription, and appropriate criteria for assessing effectiveness. In this paper, I summarize what areas are becoming consensual among most writers on effectiveness, and I point out continuing areas of disagreement and conflict. The five statements summarizing consensual characteristics of effectiveness and the three statements summarizing areas of continuing conflict point out that agreement about effectiveness is mainly an agreement to disagree. Conflicts center mainly on the incompatibility and inappropriateness of commonly selected criteria. The main theme of the paper, however, is a discussion of an inherent, but largely ignored, characteristic of effectiveness in organizations—the paradoxical nature of effectiveness criteria. This discussion illustrates that the most effective organizations are also those characterized by paradoxes—i.e., contradictions, simultaneous opposites, and incompatibilities. Taking account of this characteristic helps explain one reason why so much confusion and disagreement continues to surround effectiveness, and it uncovers a new set of research questions that can guide future investigations. Some suggestions are provided for how research on paradoxes in effectiveness might be pursued in the future.