The European Stability Mechanism (ESM) is an intergovernmental organization located in Luxembourg City, which operates under public international law for all eurozone Member States having ratified a special ESM intergovernmental treaty.

It was established on 27 September 2012 as a permanent firewall for the eurozone, to safeguard and provide instant access to financial assistance programmes for member states of the eurozone in financial difficulty, with a maximum lending capacity of 500 billion.