The way of selecting school principals is crucial, as the profile of the teachers leading the schools depends on this. This paper deals with the procedures and selection criteria for secondary school leaders in the years 2002, 2007, 2011 and 2015. Specifically, through the examination of the relevant legislation, it attempts to compare the processes, to identify their similarities and differences and to highlight the predominant selection criteria each time. The study shows that there is not a stable selection frame to education, since the current political leadership changes it. The criteria which decisively weighed in each process were different. In three of the four examined selection procedures the criteria according to the relevant laws were not applied all, and, finally, the subjectivity concerning the evaluation of candidates’ personality and general assembly was present in all selection procedures.