This article reports on a study of foreign students' success in higher education in Norway and focuses specifically on the relation between academic success and students' proficiency level of Norwegian as measured by a CEFR-based university entrance test. This study is distinguished from prior studies because it sets out to investigate not only the relation between entrance test score and future academic success but also what level of target language proficiency is a necessary minimum requirement for foreign students to manage the linguistic demands they face in higher education. It includes students who passed the entrance test in question as well as students who failed, hence overcoming a common limitation of predictive validity studies. The results of the study show a significant positive correlation between scores on the university entrance test and self-reported academic success. Moreover, the study shows that students with proficiency levels below B2 seem to lack the necessary language skills to master their studies, regardless of discipline and faculty. The results are of relevance to other countries and educational contexts where the CEFR scale is used as a reference for university entrance tests. Together with similar studies of the predictive validity of CEFR-based entrance tests, the study contributes to an ongoing validation of the CEFR, which has been called for since its publication.