Geography education in Portugal is still very much attached to what can be defined as a descriptive and factual approach, which seems to prevail in spite of all the changes introduced in the design of school geography. Given this context, the paper intends to foresee the process that leads to the standardization of teachers' knowledge and practices within the paradigm of social representations. The methodological approach followed the interrogative methods usually applied to apprehend the content and the structure of social representations' systems, which included in-depth interviews and the content analysis of teaching materials produced by teachers. Results show that the standardization of geography teachers' practices can be understood as an outcome of two interconnected processes: (1) the development of teachers' social representations systems, which are envisaged as the foundation of teachers' subject and professional knowledge; (2) the development of their professional identity. Geography teachers' professional identity is conceived as a network build around elements that belong to their professional representations, a network that is activated when teachers are confronted with a specific inter-relational context, which requires their identification with or differentiation from the group to which they have to cope with at a specific time and professional circumstances.