Federal and highly decentralized political systems open different spaces to interpret, adapt, and enact international policy trends and ideas within the same territory. Spain, a country with a highly decentralized educational system and contentious territorial politics, is a very suitable case to analyze these dynamics. Spain and its different regions have not been immune to the influence of global policy ideas that gear around promoting private provision, school choice, and New Public Management (NPM) in education. However, the consolidation of the decentralization project, together with the fact that many regional governments have aimed to construct, for a variety of reasons, singular political profiles, have resulted in markedly different policy trajectories. To show this, this article pays particular attention to recent changes in the educational governance arrangements of two important Spanish regions, Madrid and Catalonia, as they have gone through differentiated processes of educational reform. Albeit the two regional education systems share important features (such as a historical and wide-scale public-private partnership for school provision), they have engaged with, combined, and mobilized exogenous and endogenous privatization policy ideas in remarkably different ways. The article delves into the political drivers behind this policy differentiation process by paying special attention to the relations of coordination, conflict, and competition that prevail within an incomplete federal system, such as the Spanish one.