Objective: Alexithymia have the similar negative consequences for mental health in adolescence as in adulthood. However, there is no alexithymia scale for clinical and research purposes in Turkish adolescents. This study aims to evaluate the psychometric properties of the Turkish version of 20-Item Toronto Alexithymia Scale (Turkish TAS-20) in a Turkish adolescent sample. Methods: Turkish TAS-20 was administered to 948 adolescents aged between 12 to 17 years (439 male and 509 female). The participants were grouped as total sample (12-17 years old), younger (12-14 years old) and older (15-17 years old) adolescents. Cronbachs α coefficients, mean inter-item correlations, intercorrelations of factors, confirmatory factor analysis, and measures of goodness-of-fit were determined. Results: The Cronbachs α coefficients were 0.78 for the total scale, 0.80, 0.68, 0.40 for the factor 1, factor 2, and factor 3, respectively. The Cronbachs α coefficient for full scale was favorable for total group. The Cronbachs α coefficient for factor 3 was reasonable in older (0.55 for 15-17 years old), however, it was low in younger adolescents (0.20 for 12-14 years old). All criteria of goodness-of-fit met the standards for adequacy-of-fit for all age groups. The mean inter-item correlation coefficients for the total sample, 12-14 year old group, and 15-17 year old group were 0.15, 0.11, and 0.21, respectively and were in the acceptable range of 0.10 to 0.50. Conclusion: The psychometric properties of Turkish TAS-20 for adolescents were comparable with the results of the reliability and validity study of Turkish TAS-20 in Turkish adults. However, caution should be taken when interpreting the results, because factor 3 appears to have weak psychometric properties. Considering factor 3, we suggest that the Turkish TAS-20 best fits for adolescents who are older than 14 years old. [Anadolu Psikiyatri Derg 2017; 18(4.000): 362-368]