The aim of this research is to examine the roles and competencies of school principals working in project schools in terms of accountability, based on the views of school principals. This is a qualitative research which is based on the phenomenology design. The working group is chosen among the most well-known project schools in Istanbul using the maximum variation sampling method. Interviews were held with 12 school principals working at the Science High School, Anatolian High School, Social Sciences High School and Anatolian Religious High Schools in the 2019-2020 academic year. The data obtained from the interviews are coded using content analysis method and different 3 themes such as supervision, the functioning of education and integrity are obtained. In this context, it is indicated that project school principals felt themselves accountable most since they have a right to determine the managers and teachers they want to work with. It came to the conclusion that school principals cooperate with their internal and external stakeholders in all matters for the development of their schools.