The theme of this essay is how to engage with unconscious dynamics in our analysis of institutions. The essay clarifies the ways in which the unconscious influences institutional structures and organizational practices, and this is the main theoretical contribution to organization studies. A conceptual framework is presented that can help scholars of organizations and institutions to deepen analysis and understanding of how people’s organizational lives can be shaped by dynamics that are beyond reason, as well as how such dynamics are embedded in social structures. The terms unconscious and institution are aligned to illustrate a new concept, ‘institutional illogics’. This refers to the structuring and unsettling effects of unconscious dynamics, particularly social defences and shared fantasies, on organizations and institutions. Examples from published, empirical papers are used to illustrate the value of the framework. The concept of illogics is intended to encourage balance alongside the influence of logics on institutional analysis.