Intimacy as experienced in best friendships was studied with respect to sex differences and sex roles, the development of components of intimacy in childhood and adolescence, and the possible interrelationship of intimacy and ego identity. Instruments included items from: (1) The Self-Perception Inventory; (2) The Gender-Role Assignment Scale; (3) The Sharabany Intimate Friendship Scale; (4) Marcia Incomplete Sentences Blank; and (5) Sharabany Scale-Revised. Results from a sample of 218 individuals aged from 8 to 14 showed that some components of intimacy develop earlier than other components; and that traditional sex differences in intimacy are better explained as sex role differences in which females and androgynous males form a homogeneous high intimacy group, while sex-typed males score significantly lower. Sex-typed individuals also seem more likely than androgynous individuals to view aspects of friendship as appropriate for one sex over the other. Results from a sample of 52 college undergraduates suggest that high intimacy in pre-college years may be associated with high levels of ego identity at the end of adolescence. A six-page reference list is appended. (Author/PN)