Studies on the privatization of education often provide explanations based on external pressures that cause policy convergence on the expansion of private provision. This article assesses this convergence by testing the propositions of policy diffusion theories and arguing that the explanations of the recent privatization wave need to incorporate the interaction between diffusion mechanisms and domestic factors. Through a paired comparison between Chile and Argentina, the study shows that the combination of external pressures with domestic support from the government and an absence of domestic contestation were crucial for global privatization ideas to be fully adopted in Chile, while in Argentina the absence of domestic factors accounted for a partial policy emulation. The article concludes that although coercive, mimetic and normative diffusion constrained policymakers' choices, domestic interests produced a variety of responses to these pressures.