In many African countries, English is the medium of instruction in higher education even though students may not always be entirely familiar with "standard" English. This study aimed at investigating the relevance of English language competencies for teaching and learning from the perspective of students and lecturers. The study was carried out in Namibia and guided by the conceptual framework of implicit theories. Through a self-administered questionnaire, data were collected from a sample of 286 undergraduate students and 34 lecturers. Students and lecturers differed statistically significantly in all their views on the topic under investigation. While most of the lecturers (85.3%) believed that their students would not have good English language competencies, the majority of students (87.8%) rated their English between good and excellent. Most lecturers believed that insufficient English language competencies would cause a variety of problems for students such as having difficulty expressing themselves in English, following lectures, taking good notes during lectures, understanding academic texts, and writing coherent essays; in contrast, the majority of students believed that they had no such problems. The results are discussed with regard to practical implications for teaching and learning in higher education.