This article analyses the case of Rosa Sensat teachers' movement in Catalonia during the final years of Francoism and the transition to democracy in Spain (1965-1990). This movement was a key actor in education reform debates in that period. Based on the perspective of political process theory, the article focuses on the contextual, organisational and discursive dynamics that define the Rosa Sensat movement, and its role as a sociopolitical actor in three historical periods: (1) the moment of emergence, linked to the dissident schools (1965-1970); (2) the process of transition to democracy and educational decentralisation, marked by the difficulties in reforming public education (1970-1977); and (3) the post-transition period, marked by the new constitution, the integration of dissident schools into the public system (1978-1990) and the marginalisation of the movement. The conclusions highlight its influence and subsequent decline as a sociopolitical actor in education reform.