Objective: The aim of the current study is to validate and test the psychometric properties of the Adolescent Egocentricism Scale in Turkish which can be used in certain studies carried out with adolescent and adult populations. Methods: The translation of the scale was carried out in five different steps. The resulting form was applied to three different samples (N1=547, N2=656, N3=155) totaling up to 1358 university students. For construct validity, confirmatory factor analysis was carried out. For convergent and discriminant validity, the Narcissism Scale, Inclusion of the Other to the Self Scale, Aggression Scale, and Rosenberg Self-Esteem Scale were administered. For the reliability measures, internal reliability and test re-test reliability analyses were carried out. Results: As a result of the validity analyses, the original three factor structure (uniqueness, self-focus, imaginary audience) was kept. The relationships of the whole scale or of the sub-dimensions with similar of different structures were validated according to certain theoretical assumptions. As a result of the reliability analyses, the internal reliability of the whole scale was between 0.73 and 0.78, and the results of the test re-test reliability analyses were between 0.61 and 0.68. In addition, there were significant sex differences and significant differences in high and low scores of egocentricism. Conclusion: The results of the analyses revealed adequate proof for the validity and the reliability of the Turkish version of the scale and the results were discussed in light of the available literature. [Anadolu Psikiyatri Derg 2017; 18(5.000): 485-494]