The objective of this paper is to verify public school teachers' conceptions about indiscipline and to investigate behaviors and/or events that occur in the classroom and are considered indiscipline, their possible causes and ways of dealing with the problem. The literature points out that several factors help in the configuration of frame of indiscipline in schools, but it cannot be ignored as a problem to be resolved fundamentally in the teacher-student relationship, and the educational-school psychologist is therefore an important mediator in this relationship. Forty-eight public school teachers participated in this study, applying semi-structured questionnaires and accomplishing content analysis using the program ATLAS.ti 7. The teachers understand indiscipline as aggressiveness, restlessness, inattentiveness, talking, disrespect to peers and teachers, lack of zeal with material, degradation of the heritage school, emotional problems, etc. About the causes, the analysis shows the categories: "stand out familiar problems" and "personal problems", "social problems", "difficulties in the school-family partnership" and, in a smaller proportion, "didactic and pedagogical questions" and "absence of religiousness". The majority confront the problem by talking with the students and communiques to the family, trying to improve the methodology of the lessons, and just a few teachers share the situation with a director.