The purpose of this research is to determine the relationship between teachers' perception of school principals' instructional leadership and organizational commitment level. Correlative investigation model was adopted in the research. Study group of this research is composed of 329 voluntary teachers. "The instructional leadership behaviors of school principals' scale" and "The organisational commitment scale" were used to collect data. Descriptive and probative statistical techniques were used. In the results of the research; it is found that determination and sharing school purposes by school principals were at the highest, teacher support and development were at the lowest level according to the views of teachers. The views of teachers concerning school principals' instructional leadership behaviors showed significant differences in all dimensions according to age factor, working period in the same school showed significant differences in all dimensions except for determination and sharing of school purposes dimension. Teachers showed affective commitment at the highest and normative commitment at the lowest level. Teachers' views concerning school commitment showed significant differences in affective commitment dimension according to gender and educational situation; affective and normative dimensions according to age and working period in school factors. It was found out that there were positive and medium level significant correlations in all dimensions of School Principals' instructional leadership behaviors and teachers' affective and normative commitment. Perception of teachers concerning school principals' instructional leadership behavior is high in all dimensions; their school commitment is good in the affective commitment and this perception is medium in the other dimensions. There were medium level and positive correlation between normative commitment and affective commitment with perception of teachers concerning school principals' instructional leadership behavior. The causes of the low commitment levels of the teachers should be examined by a qualitative research to push teachers' organizational commitment to higher level. Causative comparative research can be done to clarify the effect of the instructional leadership to the teachers' commitments.