Assumed determinants of ego identity were investigated in this study using sophomore, junior, and senior high school males and females. Subjects were administered the Marcia Ego Identity Status Scale and measures of sex-role identification, personality development, psychological functioning, self-concept, and parental socialization practices. Data analyses, using a median split on identity score, showed that high-identity adolescents obtained more positive scores on sex-role identification, personality development, psychological adjustment, and self-concept than low-identity adolescents. Socialization practices also differed for the two groups. The sex differences which emerged were congruent with the identity literature. Overall, the data supported Erikson's theory of ego identity development.