The project examined the predictive validity of the TOEFL iBT test with a focus on the relationship between TOEFL iBT scores and students' subsequent academic success in postgraduate studies in one leading university in the United Kingdom, paying specific attention to the role of linguistic preparedness as perceived by students and tutors. We employed a mixed-methods approach to enrich traditionally quantitatively oriented studies with a qualitative perspective. For the sample of 504 students who entered the university for postgraduate studies in the years 2011–2013 on the basis of a TOEFL iBT score, we analyzed the relation between TOEFL iBT scores and final academic award by correlation and regression analyses, taking into consideration discipline, nationality, and additional language support. For the qualitative strand, students entering the university in 2013 on the basis of a TOEFL iBT score were invited to complete questionnaires and interviews, as were their English for academic purposes and academic tutors. A total 48 students and 58 tutors participated, with 25 students and 36 tutors being interviewed at 3 points over the course of the year. Our findings show that students entering the university on the basis of TOEFL iBT scores feel well prepared and generally regard the test as an effective means of preparation for their academic studies in a U.K. setting. They cope well with linguistic demands, and a vast majority graduate successfully. Our findings support the appropriateness of the university's entrance policy with regard to setting minimum test score requirements, thus underpinning the predictive validity of TOEFL iBT in a U.K. setting.