Reflective skills are widely regarded as a means of improving students' lifelong learning and professional practice in higher education (Rogers 2001). While the value of reflective practice is widely accepted in educational circles, a critical issue is that reflective writing is complex, and has high rhetorical demands, making it difficult to master unless it is taught in an explicit and systematic way. This paper argues that a functional-semantic approach to language (Eggins 2004), based on Halliday's (1978) systemic functional linguistics (SFL) can be used to develop a shared language to explicitly teach and assess reflective writing in higher-education courses. The paper outlines key theories and scales of reflection, and then uses SFL to develop a social semiotic model for reflective writing. Examples of reflective writing are analysed to show how such a model can be used explicitly to improve the reflective writing skills of higher-education students. (Contains 2 tables and 4 figures.)