The case study reported in this chapter explores how four Chinese and Vietnamese international students from two disciplines, Economics and Education, mediated their ways of displaying critical thinking in disciplinary writing at an Australian university. It draws on a modified version of Lillis’s (2001) heuristic and positioning theory (Harre´ & van Langenhove, 1999) for the interpretation of students’ writing practices within an institutional context. The study includes four talks around texts, which engage the students in an exploration of their practices in demonstrating their critical thinking in their first texts at the university, and four in-depth interviews six months later, which aim to examine how students negotiated their writing practices as they progressed through their course.