The effect of anxiety on school success has been studied. STAI, which has been developed by Spielberger and adapted to Turkish by Le Comte and Necla Oner has been used as the evaluation instrument. Both school grades and University Placement Examination (OSYS) scores have been used as measures of success. As a result, it has been deduced that anxiety affects both school and University Placement Examination performance negatively. Additionally, it has been found that success in school affects success in the University Placement Examination. The reliability of the measurement done using STAI has been tested using Cornbach alpha and Kuder Richardson methods. The reliability of the results has been found out to be high.