Objective The purpose of this article is to describe the development process of a research instrument, in the format of a self-report scale, to investigate the school psychologists’ profile, their competencies and professional activities indicators. It is based on the historical-cultural psychology, critical school psychology, and competence approach. Method The method used a review of evidence of theoretical and semantic validity of a scale for profile and competencies contains three guiding lines: (a) instructions and sociodemographic characterization of the participant, (b) profile and competencies of the school psychologist (40 items), and (c) school psychology practices (30 items). Several procedures were carried out for the development and validation of the instrument. The initial version was reviewed by two groups of expert judges, from Brazil and Portugal. The judges’ review led to the removal of some items. The new version was submitted to pilot studies for theoretical and semantic validation. Results As a result of these validations, the most recent version of the scale was obtained for use in Brazil and Portugal. Conclusion It is expected that the instrument will contribute to the theoretical-conceptual and methodological expansion of the psychologist’s profile, affecting how interventions will be carried out in educational and academic spaces from an institutional and collective perspective.