Being part of a larger project on teachers' professional identity, this interpretative research purports to (a) identify the teachers' ethical conceptions that permeate the teaching praxis; and (b) characterize similarities and differences across subjective ethical perspectives and arguments pertaining to dimensions of professional practices. Results show that professional work is commanded by a multiplicity of duties regarding profession, school, students, parents, and colleagues. Duties relative to students appeared to be more encompassing and consensual than the others. Duties regarding parents were less referred. Young teachers attributed a greater relevance to consensus regarding teaching aims and methods, professional rigor and commitment than more experienced teachers which, in turn, valued collegiality and scientific actualization. The highest school duties frequencies regard preservation of the school order while abiding by the State norms, contributing to the pedagogical quality and debates on school and educational values. Implications concerning the specificity of the Portuguese school governance and administration, the teacher education system and career are discussed.