ABSTRACT The purpose of this research is to learn about teachers’ conceptions of differentiated assessment and curricular flexibility in inclusive contexts. The great challenge facing teachers today is to ensure that all students, regardless of their individual characteristics, actively participate in the educational process and achieve quality learning. The design of this research was qualitative with a single case study approach and three data collection techniques: semi-structured interview, focus groups and document analysis, the participants of this study were 10 teachers from 3 educational institutions. The main results show that teachers handle a paradigmatic problem when referring to concepts such as integration and inclusion, which leads to a cultural barrier and jeopardizes the possibility of building an educational system with equity. Regarding differentiated assessment, teachers recognize its importance and concept, but basically accuse lack of time and training for its implementation, working as a pedagogical strategy and not as a teaching methodology.