The Utrecht-Management of Identity Commitments Scale (U-MICS) is one of the most-commonly used self-report scales to assess personal identity in studies of developmental processes. While it has been translated and validated in many countries around the world, evidence of its applicability in Greek is absent. The purpose of this study was to examine the factor structure of the Greek version of the U-MICS, and to test its measurement invariance across time and across ethnic groups living in Greece. Using data from 811 adolescents (M[subscript age] = 12.57, SD[subscript age] = 0.49 at Wave 1, 45.9% girls, 47.1% immigrant), Confirmatory Factor Analyses on the Greek U-MICS supported its well-established three-factor structure. Even though testing invariance of the educational U-MICS showed mixed results, the factor structure and the measurement properties of the interpersonal U-MICS were found to be comparable across ethnic groups, and across three years of junior high school. Finally, the bivariate associations of the three dimensions of the U-MICS with indices of adaptation (self-esteem, and emotional symptoms) partially supported the convergent validity of the scale. This study adds to the existing pool of studies supporting the applicability of the U-MICS in different languages and ethnic groups.