This paper investigates the teacher’s perception and knowledge about interdisciplinarity on public secondary school in Rio de Janeiro. Among the participants, 101 teachers completed the questionnaire on the subject investigated. All data about the perceptions of teachers were faced with lesson plans prepared by teachers who reported having strong knowledge on interdisciplinary practice. Our results suggest that there is a lack of support in schools, and competence of teachers to develop interdisciplinary approaches in the classroom. In this context, we suggest the use of methodologies such as Problem-Based Learning in teacher training courses in Brazil, as well as encouraging a continuing education of professionals through postgraduate programs.