This study aims to provide empirical evidence supporting the largely anecdotal observations and perceptions that teachers, in their assessment of student writing, are operating within a hidden curriculum. Most of the research done locally has so far concentrated on teachers' actual comments on students' scripts, pointing to their almost exclusive emphasis on form ('form' being the surface-level features such as grammar, spelling and punctuation) rather than content ('content' being the umbrella term for content, characterization and organization) in teachers' response to students' writing (Chee, 1996; Lee, 1998), students' response to teachers' feedback (Chee,1996), and the usefulness of the genre-and-register approach in the teaching of recounts and argumentative essays (Pereira, 1995; Teo, 1998). My study aims to fill the gap in local research by examining the 'hidden curriculum' of local secondary teachers in their assessment of narratives. The teachers' 'prescriptive' comments on the students' scripts will be compared against their 'diagnostic' comments made on the diagnostic evaluation sheets unavailable to students, to see if there is any mismatch with regard to the focus for the prescriptive comments that the students receive and the focus for the diagnostic comments that they do not receive. Any mismatch would suggest that teachers are working within a hidden curriculum, that is, a curriculum in which the requirements of a good narrative are not made explicit to the students. The drawbacks of teachers working within this hidden curriculum are that students have no access to the criteria of a good/ weak narrative that the teachers subscribe to in the assessment of their narratives. The teachers' diagnostic comments are also examined closely to see if they are vague and unsystematic. In addition to this examination, an analysis is done on these comments to see if there is any correlation with the linguistic and organizational features of the genre-and register approach of assessment used by Macken and Slade (1993). The last part of the study provides an illustrative sample as to how a good and a weak essay can be commented on using the metalanguage of this mode of assessment.