A central bank, reserve bank, national bank, or monetary authority is an institution that manages the monetary policy of a country or monetary union. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the monetary base. Many central banks also have supervisory or regulatory powers to ensure the stability of commercial banks in their jurisdiction, to prevent bank runs, and, in some cases, to enforce policies on financial consumer protection, and against bank fraud, money laundering, or terrorism financing. Central banks play a crucial role in macroeconomic forecasting, which is essential for guiding monetary policy decisions, especially during times of economic turbulence.

Central banks in most developed nations are usually set up to be institutionally independent from political interference, even though governments typically have governance rights over them, legislative bodies exercise scrutiny, and central banks frequently do show responsiveness to politics.

Issues like central bank independence, central bank policies, and rhetoric in central bank governors' discourse or the premises of macroeconomic policies (monetary and fiscal policy) of the state, are a focus of contention and criticism by some policymakers, researchers, and specialized business, economics, and finance media.

The notion of central banks as a separate category from other banks has emerged gradually, and only fully coalesced in the 20th century. In the aftermath of World War I, leading central bankers of the United Kingdom and the United States respectively, Montagu Norman and Benjamin Strong, agreed on a definition of central banks that was both positive and normative. Since that time, central banks have been generally distinguishable from other financial institutions, except under Communism in so-called single-tier banking systems such as Hungary's between 1950 and 1987, where the Hungarian National Bank operated alongside three other major state-owned banks. For earlier periods, what institutions do or do not count as central banks is often not univocal.

Correlatively, different scholars have held different views about the timeline of emergence of the first central banks. A widely held view in the second half of the 20th century has been that Stockholms Banco (est. 1657), as the original issuer of banknotes, counted as the oldest central bank, and that consequently its successor the Sveriges Riksbank was the oldest central bank in continuous operation, with the Bank of England as second-oldest and direct or indirect model for all subsequent central banks. That view has persisted in some early-21st-century publications. In more recent scholarship, however, the issuance of banknotes has often been viewed as just one of several techniques to provide central bank money, defined as financial money (in contrast to commodity money) of the highest quality. Under that definition, municipal banks of the late medieval and early modern periods, such as the Taula de canvi de Barcelona (est. 1401) or Bank of Amsterdam (est. 1609), issued central bank money and count as early central banks.

There is no universal terminology for the name of a central bank. Early central banks were often the only or principal formal financial institution in their jurisdiction, and were consequently often named "bank of" the relevant city's or country's name, e.g. the Bank of Amsterdam, Bank of Hamburg, Bank of England, or Wiener Stadtbank. Naming practices subsequently evolved as more central banks were established. The expression "central bank" itself only appeared in the early 19th century, but at that time it referred to the head office of a multi-branched bank, and was still used in that sense by Walter Bagehot in his seminal 1873 essay Lombard Street. During that era, what is now known as a central bank was often referred to as a bank of issue (French: institut d'émission, German: Notenbank). The reference to central banking in the current sense only became widespread in the early 20th century.

Names of individual central banks include, with references to the date when the bank acquired its current name:

In some cases, the local-language name is used in English-language practice, e.g. Sveriges Riksbank (est. 1668, current name in use since 1866), De Nederlandsche Bank (est. 1814), Deutsche Bundesbank (est. 1957), or Bangko Sentral ng Pilipinas (est. 1993).