In 1988, linguists James P. Lantolf and William Frawley stated that, in the quest to characterize just what exactly is meant by language proficiency, “we are no closer to understanding the concept today than we were 20 years ago” (Lantolf & Frawley, 1988, p. 185). Another quarter century has passed since Lantolf and Frawley’s disheartening declaration, yet the question remains: How do we untangle the construct of proficiency? Although theoretical and empirical efforts over the years have attempted to identify the components of proficiency, anything resembling a consensus has yet to be reached. With more than four decades devoted to delineating this seemingly simple idea, doubt emerges as to whether a single definition indeed exists that can satisfy the factions of professionals in the second language acquisition field. However, recent paths of thought have trod in a promising direction. Researchers are painting a more sophisticated picture of proficiency through the application of measurable linguistic features to traditionally subjective competency descriptions. As this linguistic quantification process continues, we can begin to examine how a deeper, more precise understanding of proficiency can inform the curriculum and assessments that determine student readiness to enter university study. Thus, this paper serves two purposes. First, it reviews historical and contemporary interpretations of proficiency and, in doing so, outlines the measurement strategies in use in the realm of English for academic purposes. Second, it crosses the bridge from English proficiency testing to university academia, analyzing the factors in play in student academic readiness and the role of language proficiency in student success.