The Goethe-Zertifikat C2: Großes Deutsches Sprachdiplom (formerly Zeugnis über die Zentrale Oberstufenprüfung) is a Goethe-Institut certificate proving high-level German language ability.
The exam Zentrale Oberstufenprüfung requires the examinee to understand difficult texts and to communicate eloquently in both spoken and written language.
It is also valued as a qualification proving mastery of German in business contexts.
The Zentrale Oberstufenprüfung may only be administered to people at least 16 years old who have not learned German as a native speaker.
The requirement for a person undertaking the ZOP is estimated at around 1,000–1,200 hours of German language lessons.