The main objective of this research is to understand how textual coherence is made in the written productions of students in the 12th grade, as well as to identify the causes that are at the origin of problems of textual coherence in order to improve the quality of their writing since they are at an advanced level of schooling. Thus, through the interview, the questionnaire as well as the texts produced by students, the literature consultation we found that they have difficulties in producing texts applying the mechanisms of cohesion and in particular textual coherence. We also found that there is an occurrence of expressions that enunciate abnormal situations for the reader and there is the irrelevance of some cognitive elements. With that, in response to the research question initially put forward: What are the strategies used by teachers for the improvement of students' writing regarding textual coherence, we found among several aspects, that there is a certain lack of delivery on the part of teachers who limit themselves to stating that the problems students face come from previous classes.