This article develops a framework for understanding and analyzing the intermediary work of platform technologies, and their owners, as an emerging form of platform governance in educational systems. Our investigation is guided by two questions: (a) How do platform technologies shape policy by brokering relations among commercial, technical, and educational actors? And (b) how might these relations contribute to, or compromise, educational equity as they are folded into existing governance regimes? We address these questions by bringing together two critical orientations--critical policy analysis and critical platform studies--to map the power and politics of platformization in and across education systems.