Yes. An opposition against an EU trademark application can be based on certain non-EU earlier rights, provided those rights are recognized under EU trademark law.
An earlier national trademark registered in any EU member state, or a trademark registered under the Madrid Protocol designating the EU, can form the basis of an opposition. Well-known marks within the meaning of Article 6bis of the Paris Convention can also be relied upon, even if unregistered, provided the mark was well known in at least one EU member state at the relevant date.
Trademarks registered solely outside the EU, with no EU designation or member state registration, cannot form the basis of an EUIPO opposition.