Accountability has become a key concept in both public administration and democratic theory. Its meaning is contested, but the general definition “obligation to answer for the performance of duties” would fit most versions. In this sense, accountability is a relationship between two parties—the person or organization answering or being held to account (the accountor or agent) and the person or organization to whom the account is owed (the account holder or principal). Analysis of accountability therefore begins with the double question: Who is accountable to whom ? Accountability obligations depend on the terms of the relationship and on its institutional context, leading to two more key questions: (1) For what is the accountor accountable and (2) how ? This entry covers the following topics: defining accountability, typologies of accountability, mechanisms of public sector accountability, democratic accountability, accountability in international relations, single versus multiple accountability, accountability in networks, and accountability and ...