This paper aims to demonstrate how linguicism, a kind of “linguistically argued racism” (Phillipson, 1992), concealed by existing requirements of writing assessment based solely on ‘standard’ academic varieties of English contributes to the language-based discrimination of international students at an Australian university. In order to achieve the purposes of this study, we will provide evidence from one context on how students’ performance on graded assignments (as marked by the course lecturers) correlates with their language proficiency (as measured independently by trained language experts). After looking at the quantitative data, we will present detailed linguistic analyses of students’ writing to show how texts written by students from a North American, British, and Australian (NABA) background differ from texts written by students from a South and South East Asian (SESEA) background. The findings from these analyses will be used to discuss the role of World Englishes and race in assessment practices in higher education.