It's no surprise that most of the courses at Austrian universities are taught in German because it's the country's official language. There are more English language programs available at postgraduate than undergraduate levels, particularly on courses that offer the most international reach, including media, marketing, and Business related subjects, among others. However, taking German classes is best if you want to fully immerse yourself in student life. There are over 300 courses taught entirely in English and another 85+ partially in English. You may need to prove your competency at a B2 or C2 level on the Common European Framework for Reference for Languages (CEFR). You can do this by taking the Österreichisches Sprachdiplom Deutsch (ÖSD), Austria's officially examination system for international students who need to study German as a foreign language. You can take the ÖSD at centres in more than forty countries worldwide. You could also take an intensive German course as a part of the University Preparations Programme if you have not already proved your proficiency in the language before.