Adopting a theoretical elucidation perspective, this article first of all examines the various conceptions of the nature of effectiveness and of the characteristics of effective organizations. It attempts to dissipate the confusion surrounding these conceptions, to identify what distinguishes them, and to reveal the beliefs they convey as well as the reasoning they employ. The differences between the conceptions lie mainly in the way they consider the expected performance of the organization as well as the relationship between their characteristics and that performance. More fundamentally, it is the representation of the organization that underlies them. In the light of the above, the article goes on to examine the literature devoted to the effectiveness of educational organizations. The conclusion proposes an assessment of their effectiveness on the basis of performance expectations formulated by the constituents and the adoption of a revised configurational perspective in research designed to identify the characteristics of effective organizations.