Market demands force organisations to seek innovation and deliver quality products in order to meet customer expectations. Specifically, the aerospace industry must endeavour to deliver quality and reliable products and services, since it is directly linked to safety. To meet these requirements, companies are seeking to develop and maintain a Quality Management System (QMS). In order to keep the QMS in place, companies seek certification to ISO 9001 and, to do this, they have to go through a process of audits, including internal audits carried out by suitably qualified auditors, who first need to be selected on the basis of competence criteria. In view of this, the aim of this research is to identify and classify in order of importance the competences of internal QMS auditors, based on research carried out in Brazilian aircraft manufacturing companies, in order to contribute to the selection of internal auditors.