English proficiency, pedagogy, and confidence: what really matters in EMI teaching?

English-medium instruction (EMI) lecturers in many European universities already command high English proficiency, leaving open the question of what else shapes their classroom practice. We surveyed 978 STEM teachers across 21 Swedish universities to examine how self-rated language proficiency, pedagogical training, and teaching self-efficacy relate to preferred teaching approaches (interactive, organised, transmissive, unreflective). Logistic-regression analyses showed that teachers with formal pedagogical training were about 2.5 times more likely to adopt interactive methods, while higher self-efficacy provided additional leverage. Incremental differences in English proficiency had only a modest effect, principally helping teachers avoid unreflective practices. These findings challenge the view that language skill is the main constraint on EMI quality once a high-proficiency threshold is met. We argue that effective EMI teacher development programmes should move beyond language enhancement to comprehensive professional development that strengthens pedagogical expertise and confidence—an intervention mix likely to yield greater gains in interactive teaching than narrow language-focused support.