The purpose of this study was to discover school administrators' principals' instructional feedback during their supervision tasks regarding classroom observation. The research was carried out with a qualitative research design and a semi-structured interview technique was administered to collect the data. The data were analyzed with content analysis technique. The participants were 23 public school teachers working in Istanbul, Adiyaman and Sanliurfa provinces in Turkey in 2018-2019 school year. They were determined with purposive sampling technique. Results reveal that school principals show poor competency in supervision work and perform the classroom supervision task once a year as a necessity of the formal procedure. Comparing to educational supervisors, results show that school principals may be more useful because they know the teacher and know the general operation of the school. Results also demonstrate that teachers do not benefit from the feedback given by the school principals, because they are claimed to give general suggestions. It is therefore incumbent on administrators to learn how to supervise teachers to support schoolwide instructional improvement. School principals should recognize how their own position within the supervisory system influences the feedback they provide to teachers.