The professional standards for teachers provide the competences needed for this occupation, in function of the level of education and of the career stages. This study aims to discover the most important training factors which contribute to the acquisition of teacher competences and to establish the implications for teacher education. We have used a mixed-method design as the procedure for collecting, analyzing, and combining both quantitative and qualitative data. To detect the main agents in the teacher competences’ achievement, we applied a questionnaire and we asked the personal opinion of the teachers regarding their evolution in the career. The findings indicated that the principal factor was the individual study, followed by the continuing professional development, through training courses, the collaborative learning, and, almost on the last place, the initial teacher education. Implications for teacher education: the changes in the future are incalculable, so we have to rethink the teacher education to ensure future teachers able to learn and adapt themselves to different conditions. We appreciate the recommendations to reform teacher education in the context of lifelong learning very useful (Dolan, 2012) and we will study the applicability of them in our university.