The Banco de Portugal is the Portuguese member of the Eurosystem and has been the monetary authority for Portugal from 1846 to 1998, issuing the Portuguese escudo. Since 2014, it has also been Portugal's national competent authority within European Banking Supervision. The bank was founded by royal charter in 1846, during the reign of Queen Maria II of Portugal, by a merger of the Banco de Lisboa, the first bank founded in Portugal, and insurer Companhia Confiança Nacional.

The Eurosystem is the monetary authority of the eurozone, the collective of European Union member states that have adopted the euro as their sole official currency. The European Central Bank (ECB) has, under Article 16 of its Statute, the exclusive right to authorise the issuance of euro banknotes. Member states can issue euro coins, but the amount must be authorised by the ECB beforehand.