In recent years, the growing number of students with English as an Additional Language (EAL) in higher education around the world - and specifically in traditional English-speaking contexts - has led to a focus on their English language proficiency (ELP). Much of the scholarly literature on the topic has drawn on expert opinions rather than the views of students themselves. Students have been treated as ‘objects of study’ rather than as ‘subjects of study’ in their own right. Student conceptualisations of ELP, which lie at the core of this thesis, are examined and analysed with respect to key variables in order to investigate whether there is any systematic variability in them, and then compared with measurable graduating outcomes. The study also compares student views with policy discourse and the theorisation of ELP in order to ascertain the degree of convergence, and to consider implications for policy and practice. In this way, the study aims to provide empirical evidence to progress what is known about the construct of ELP in the higher education context.