In recent years, universities across Europe have increasingly adopted the use of English as an academic lingua franca. Our article discusses current trends in Swedish higher education by presenting the results of a large-scale survey on the use of English conducted at Stockholm University. The survey involved 668 staff and 4524 students and focused on the use of English for academic purposes and students' and teachers' attitudes to English as a medium of instruction. The results indicate that complex patterns of academic English use emerge, which are related to the specific discipline studied, the level of instruction (undergraduate versus Master's) and the receptive versus productive use of English. They also indicate that in the sciences the use of English is a pragmatic reality for both teachers and students, whereas in the humanities and social sciences, English is typically used as an additional or auxiliary language in parallel with Swedish. (Contains 3 tables and 6 figures.)