This study explored the Mexican system to appoint school leaders from a perspective that could consider its positive aspects and as well as its shortcomings. This research was framed as an exploratory case study. Three types of participants were interviewed: five aspiring heads, twelve incumbent heads, and four administrators of the promotion system. Thematic analysis was the procedure adopted in the analysis of transcripts. The research was carried out to the highest ethical standards in educational research as anonymity, confidentiality, and respect for the participants were observed all the time. The study revealed that there are some positive aspects in the Mexican system that could enable its consolidation. The study found also a need to upgrade the current system of promotion since school leaders in Mexico are appointed by a system in which its regulations and procedures were promulgated more than 40 years ago. The current system of promotion does not enable the appointment of prepared school leaders. The findings revealed a need for leadership preparation as a prerequisite for participants in competitions for deputy headships, headships and for those who are already holding a leadership position.