The present study examines lecture comprehension in English-Medium (EM) courses, i.e. non-language subjects taught through English in higher education. It uses a questionnaire with self-assessment items for aspects of lecture comprehension in English and in the first language (L1). The sample comprises 391 respondents from three Norwegian institutions of higher education. Analysis shows that although the differences in comprehension scores between English and the L1 are not substantial, and the respondents experienced much the same difficulties in the L1 and English, a larger number of students have comprehension difficulties in the EM lectures. The main problems are difficulties distinguishing the meaning of words, unfamiliar vocabulary, and difficulties taking notes while listening to lectures. It concludes by arguing the need to take language difficulties seriously, through the use of effective lecturing behavior, and improving the lecturers’ as well as the students’ English proficiency.