The low performance of Turkey in the Programme for International Student Assessment (PISA) was a great disappointment. To investigate the likely causes for the low performance in mathematics, reading and science, this study measured the efficiency of secondary schools in different regions in Turkey. In this study, NUTS 1 (Nomenclature of Territorial Units for Statistics) was used for the regions. The sampling data consisted of the students who participated in the Programme for International Student Assessment (PISA) 2003 in Turkey. The efficient and inefficient schools in different regions in Turkey were determined by analyzing the sample data. Strategies for turning the inefficient schools into efficient were examined using output oriented CCR model. As a result of the study, it was found that 7 of the 48 schools (%14.56) were efficient. Also, it was found that the most efficient region in Turkey was Istanbul and the most efficient school types were science high schools and police colleges