Banknotes of the euro, the common currency of the eurozone, have been in circulation since the first series was issued in 2002. They are issued by the national central banks of the Eurosystem or the European Central Bank. The euro was established in 1999, but "for the first three years it was an invisible currency, used for accounting purposes only, e.g. in electronic payments". In 2002, notes and coins began to circulate. The euro rapidly took over from the former national currencies and slowly expanded around the European Union.

The euro is the official currency of 20 of the 27 member states of the European Union. This group of states is officially known as the euro area or, more commonly, the eurozone. The euro is divided into 100 euro cents.