The research described in this thesis investigates features of neo-standard Italian in a corpus of school students’ texts. Special attention is dedicated to the use of indicative and subjunctive in complement clauses. In particular, restandardisation trends are observed from the point of view of the students’ usage, the corrections applied by teachers and the instructions of school grammar books; this analysis allows drawing a general profile of the attitude of Italian schools towards neo-standard traits. The second part of the thesis is dedicated to analysing mood variation in complement clauses. First, a review of the literature on complementation, modality and Italian subjunctive is outlined, with special attention to its disappearance; then, the phenomenon is investigated in the data collected in the schools that took part in the research. Secondly, the acceptability of indicative in lieu of subjunctive in texts written at school is further investigated by means of a correction test administered to the teachers. The final part of the thesis contains a detailed analysis of school grammar books, whose treatment of the subjunctive is compared to the scientific literature; this chapter allows to complete the picture regarding the attitude of Italian schools and to make proposals related to grammar teaching.