The European Commission has undergone successive waves of public management reforms since the second half of the 1990s that have led to substantive administrative change. This contribution aims at explaining how the "unique" politico-administrative context of the European Union affected the trajectory of reform of the Commission, compared with trajectories of reform of the public sector at the national level. On the basis of such analysis, the Pollitt and Bouckaert model of contextual influences on the dynamics of public management reform is revisited, and considerations on the use of historical institutionalism in the study of administrative reforms proposed.