This study based on a theoretical framework of three main environmental perspectives in the human-nature relationship (anthropocentrism, biocentrism and ecocentrism), aimed to identify their incidence in teachers involved with environmental projects when confronted with diverse environmental issues. 60 teachers drawn from four school cycles in Portugal (creche; 1st cycle, 6-9 years old; 2nd cycle, 10-11 years old; 3rd cycle and Secondary school, 12-17 years old) were interviewed and divided into two groups: generalist teachers (creche and 1st cycle) and specialists in different subjects (2nd and 3rd cycles and secondary). The results showed a higher occurrence of biocentric perceptions in all teachers (more significantly in those from the 1st group). Comparatively, the teachers from the 2nd group showed more ecocentric perceptions. These differences can be explained by the models of teacher education (initial and inservice) and by the influence of the specific characteristics of the cycles in question. In contrast, the teachers' environmental projects were mostly centred on sustainable use of resources, which inevitably favours anthropocentric arguments. The results allow us to conclude that different environmental approaches are possible, especially if teachers are aware of the importance of dealing with more controversial environmental issues.