Autonomy and self-assessment are crucial elements to be developed in the process of foreign language learning according to the Council of Europe recommendations. The European Language Portfolio is conceived as a tool that allows users to record their language learning achievements and their experience of learning and using languages. This paper presents the results of a study carried out in Spain on Primary education level with the ELP as the working basis to engage students in their own learning process. The analysis of the results offers insights on learners’ autonomy and self-assessment, plurilingualism, diversity awareness and usefulness of the ELP from both the teacher’s and students’ perspective.