Purpose: This paper proposes a new conception of school systems arising out of the collision of three forces--(1) a longstanding press to rationalize the technical work of schools in the service of educational excellence; (2) a growing democratic press to equitably engage community members in the process of defining educational excellence; which together are (3) heightening legacy uncertainties that pervade educational organizations. It then draws on paradox theory to explore how leaders might navigate the growing uncertainties that are central to the work of organizing for excellence and equity. Design/methodology/approach: Integrating scholarship related to organizational institutionalism, paradox theory, learning sciences, social justice leadership and educational system building, this paper examines the changing organization of schools, the growing uncertainty facing educators and the implications for leaders and preparation programs. Findings: This paper introduces two perspectives on how to navigate the growing uncertainty facing educators and educational leaders--one that centers on mitigating uncertainty, the other that prioritizes leveraging uncertainty. Both perspectives have affordances and limitations when considering the twin goals of educational excellence and equitable involvement in decision-making, and leaders should thus view uncertainty as a paradox--an interdependent, persistent, contradiction--that can never be fully resolved, but can be managed. A paradox perspective makes visible the complex work of effectively moving between mitigating and leveraging uncertainty, especially in a field where the latter garners more support and legitimacy. Originality/value: This paper synthesizes recent educational and organizational scholarship to develop a new conception of educational organizations and a corresponding approach to educational leadership capable of navigating the growing complexity and uncertainty that pervades school systems.