Gender differences in self-esteem across time were investigated by means of a comparison of the extent of congruence between an individual's self Q-sort and his or her Q-sort of the ideal self. Self Q-sorts were done when subjects were 11, 14, 18, and 23 years of age; they were done on separate occasions, at least a week apart. Ideal self Q-sorts were obtained when subjects were 14, 18, and 23. Subjects were 50 females and 45 males who had been studied from the age of 3 years. All analyses are for the sexes separately. Findings point out: (1) the shared and unshared self and observer attributions of those males and females with high self-esteem; (2) the consistency and reliability of self-esteem Q-based congruence scores; (3) sex differences in level of self-esteem over time; (4) the nonsignificance of social class for ideal self-attributions at any age for either sex; (5) the relation of ego-control to self-esteem; (6) the similarity of individuals' self-descriptions over time; and (7) problems associated with use of the Rosenberg index of self-esteem. (RH)