This study aims to analyze the educational sectors of six science museums in the city of Rio de Janeiro with the purpose of understanding the structure and functioning of such spaces, as well as the theoretical references underlying the educational actions developed by their professionals. The House of Science, the Museum of Geodiversity, the Museum of Life, the Museum of Astronomy and Related Sciences, the Museum of the Environment and the National Museum were selected for this research. Although studies on mediation, public, scientific popularization and the museum-school relationship have grown considerably in the last decades, the literature review offers reduced material specifically aimed at the educational sectors of science museums. Authors from different fields of knowledge – such as Museology, Education, Sociology, Science Teaching– contributed to the theoretical framework of this research, among them: Cazelli, Hooper-Greenhill, Rubiales, Valente, Wagensberg, Freire, Carvalho and Dubet. In methodological terms, I opted for a qualitative analysis of the answers given by science museums to the questionnaire once applied in 2015 by the Research Group on Education, Museum, Culture and Childhood (GEPEMCI/PUC-Rio), with special attention to the results obtained from the six museums selected for this study. Then, semi-structured interviews were conducted with museum educators who integrate the ES teams of the analyzed institutions. With these tools, data were collected concerning the profile of museum educators, the insertion of the educational sector in the institution, the training of these professionals, the theoretical references underlying their practices and the conceptions of education that guide the performance. Then a content analysis as proposed by Laurence Bardin was carried out. Combining these methods, it was possible to approach the specificities of the educational sectors of the museums under study, reflect on the theoretical frameworks used by the interviewed professionals and relate these references to the proposed educational actions. It was also noticed that these subjects often exercise multiple functions within the ES, and that professionalization of these subjects is a field in dispute, since the museum educator is not constituted as a formal profession. Their search for training process had as its starting point the experience in the educational sector and the exchange of knowledge with the actors involved. In this sense, interdisciplinarity and trajectories in different areas contribute to continuous training, carried out by and with peers. Among the interviewees, there were several conceptions of education, the role of the educational sector, the institutional mission, the importance of an educational plan and the relationship established with the theoretical frameworks that guide educational actions. Regarding the theoretical framework, the educator Paulo Freire was the most cited, followed by Piaget, Vygotsky and some national and international authors in the field of museums. The research also indicated the necessity of establishing and maintaining a proposal that unites the academy, the museum and the school in the collective construction of educational actions aimed at training, with the goal of meeting the inter-institutional demands, adding the expertise in understanding and appropriating the science museum space.