A foreign marriage certificate needs a certified German translation whenever an Austrian authority has to rely on it — the Standesamt (civil registry office) for a marriage abroad or a name change, the Niederlassungsbehörde or, in Vienna, MA 35 for a residence title based on the marriage, the citizenship authority for naturalisation, or an Austrian embassy abroad for a spousal-visa application. It must be produced by a court-sworn translator (in German, gerichtlich beeideter und zertifizierter Übersetzer), authorised under § 14 SDG and entered in the official register at a Regional Court (Landesgericht). Their round court seal — the Rundsiegel — is what makes the translation legally valid before an Austrian authority, and it is also what the Niederlassungsbehörde, MA 35 and Austrian embassies expect to see.
There is one important exception. If the marriage was registered in a country that issues one, you can often present an international multilingual marriage certificate under the CIEC Vienna Convention of 1976 (Form B), or an EU 2016/1191 standard form — both designed to be accepted without a translation among the participating states, Austria included. Where those are not available, a certified translation by a court-sworn translator is the reliable route. This guide explains which applies to you, and what else typically travels with the certificate.