School leadership plays a crucial role to quality education. Social changes have led to an increase in school principals' competencies, responsibilities, and demands. There are significant gaps in the literature on school leadership and limitations in the study of principals' responsibilities. This study aimed to analyse whether principals consider the competencies assigned to them by educational legislation to be within their scope. Participants were 394 principals from state-owned schools in Andalusia, southern Spain. Quantitative and qualitative data analyses were performed. We identified four competencies that the principals believed they were unable to effectively assume within the Andalusian educational context: (1) awarding contracts for construction, services, or supplies; (2) authorising expenditures, arranging payments, and preparing the school budget; (3) promoting the qualifications and training of teaching staff; and (4) supervising non-teaching staff in the school. This study emphasises the need of a comprehensive reevaluation of how competencies assigned to school principals are managed, highlighting the significance of incorporating principals' perspectives. For future research, we recommend exploring alternative approaches in competency management to enhance their effectiveness and relevance in the educational context.