We conducted a case study of a rural primary school in Mexico. Its teachers consented to introducing an EE model using PAR methodology. Our objective was to analyse how PAR can generate specific issue-related understandings in teachers, thus resolving the gap between EE theories and practices. We conducted a qualitative study and implemented non-participatory observations of teachers' classes, participatory observation of school routines, and elaboration of field notes. We also conducted semi-structured interviews before and after a specified period. The results showed that, before using PAR techniques, EE teachers' conception and practice were focused on providing and analysing information related to caring for the environment. Afterwards, their conceptions and practices appeared more action-oriented. These teachers were not specialists in EE and they had not had any prior related training; nevertheless, the Mexican curriculum for primary schools states that teachers should incorporate EE into their lessons with a cross-curricular perspective.