This article reports a mixed-methods study that investigates academic success in English Medium Instruction (EMI) at a Chinese state university. Questionnaire, exam score (n = 100), and semi-structured interview data (n = 29) was collected from second-year undergraduate students majoring in Business Management. Content-related language proficiency, perceived success, and motivation were explored as possible significant predictors of academic success in EMI. Business English proficiency was a statistically significant predictor, highlighting that students with a lower level of proficiency need supplementary linguistic support in order to fully succeed in their EMI studies. Language learning motivation did not predict academic success, echoing previous findings (Rose, H., S. Curle, I. Aizawa, and G. Thompson. 2019. "What drives success in English medium taught courses?" The interplay between language proficiency, academic skills, and motivation. "Studies in Higher Education" 0 (0): 1-13. doi:10.1080/03075079.2019.1590690). "Perceived success" in EMI did predict "actual success" in EMI, highlighting the need to enhance students' perceptions of their own ability to succeed in EMI. Qualitative data revealed that students' perceptions of success in EMI centred around content knowledge acquisition, improved English proficiency, knowledge application and transformation, and forming new modes of thinking. Practical implications for pedagogy are discussed.