Jean-Claude Juncker, president of the European Union's executive body, delivered his annual State of the Union address on Wednesday before the EU's parliament in Strasbourg.
In it, he said the euro is meant to be the single currency as a whole. Sweden, however, still uses the Swedish krona as its national currency.
Juncker also proposed that the EU help member states join the 19 other countries using the euro as well as establish a Europe-wide finance minister to deepen economic integration across the region.
"If we want the euro to unite rather than divide our continent, then it should be more than the currency of a select group of countries. The euro is meant to be the single currency of the European Union as a whole. All but two of our Member States are required and entitled to join the euro once they fulfill all conditions," Juncker said.
Both Denmark and the UK negotiated to opt out of the eurozone.
There are 7 EU members who are not on the euro but are expected to adopt it after meeting certain economic criteria. They are: Sweden, Bulgaria, Croatia, Czech Republic, Hungary, Poland and Romania.
Sweden has deliberated delayed joining a EU currency exchange rate system which allows it to avoid triggering the process to join the eurozone for the time being.