This chapter examines the division of power between different levels of government in European countries. Some states are unitary, while others are federal with a constitutional division of power between the centre and the federal regions. Even within unitary states there are local and regional levels of government. The major debates about centralization versus decentralization are reviewed, including arguments about economic efficiency, democratic quality, and equity. The chapter also examines nationalist movements within states and the way they have sought greater autonomy or even secession. Finally, it considers issues of rescaling—that is, the shift of power and tasks across different levels—especially in the context of European integration.