The present study aims at investigating the written production of students at a public state school in Rio de Janeiro, in order to observe the difficulties in dealing with the written language modality, considering that these difficulties can frequently bring consequences to their lives, inside and outside the school context. At school, these difficulties can cause lack of interest or motivation, whereas out of school someone who has difficulty at engaging in social practices of reading and writing (Rojo, 2010; Soares, 1998) can have fewer chances of social mobility and be led into living on the edge of society. Considering the functionality of language as well as social and contextual issues related to its use (Halliday, 1994; Martin, 2001), this research proposes the following questions: 1) What evaluation do the graduating secondary school students make upon the school, including the individuals who act, react and interact there? 2) How does this school play its role as agency of school literacy? 3) What connections can be raised between school and social inclusion and exclusion? The set of data analyzed in this study consists of essays written by secondary students in their classroom (N = 30),and answers to an online questionnaire (N=11) sent to students after they have left school, via a social media. Statistical data about the performance of Brazilian students in national and international examinations, such as PISA, SAEB and especially ENEM, were used to examine and classify data. The Appraisal system and systemic-functional perspectives supported both the analysis of the evaluation that students make of the school as a community, including themselves, and the investigation of the degree of literacy that they present in their written production. Answers to the questionnaire provided information about the educational and/or professional activities of the students after their conclusion of secondary school, adding material for the discussion of possible relations between school literacy and social inclusion. Results of the analysis indicate that students make an evaluation of the school that often varies between positive and negative, especially when related to Affection, and that the institution is personalized and valued by its social role over the educational one. Other members of the school community, such as teachers and peers, are also affectively evaluated. However, when linguistic evidences show Judgement or Appreciation, the evaluation points to a more negative positioning of students in relation to school, especially as an agency of literacy. Students texts also show that they present a very incipient degree of literacy, even after having spent nearly eleven years at school. These results lead into a discussion about the interference that literacy deficiencies can have on people s lives, such as the students who participate in this research, who can face difficulties to enter public universities and to have better jobs or careers.