This article aims to interpret an annual initiation ritual celebrated in Hellenistic Phaistos (Crete), at a festival known as the Ekdusia, in which young men had to put on women's clothes and swear an oath of citizenship before they could graduate from the civic youth corps (the agela) and enter the society of adult male citizens. It begins by reconstructing the ritual and situating it within its historical and social context. It then reviews the two major theories which have been used to explain transvestism in Greek initiation-structuralist and psychological-and attempts to expose their shortcomings. The author remedies the difficulty with the structuralist approach-its focus on abstract symbols divorced from their social context-by understanding the ritual change of clothes (feminine clothes exchanged for masculine clothes) at the Ekdusia in terms of the radical gender segregation in Cretan society and the gradual transition Cretan boys made from feminine spaces to masculine spaces in both city and home. The author remedies the main problem with the psychological approach-its focus on the psychological dynamic between mother and son rather than the motivations of the rite's adult male sponsors-by looking at how adult men, particularly in modern non-Greek societies which hold initiation rites, understand male adolescent development and create rituals in accordance therewith. This comparative model shows how men in gender-segregated societies think of boys as feminine themselves and believe that their masculine development is at risk if they are not rescued from the dangerous feminine realm, and forced to undergo a combination of defeminization and masculinization rituals. Although there is no direct evidence to suggest that Greek men thought of boys' transition rites in this way, the myths told about three different figures named Leukippos, related directly (etiologically) and indirectly to the Ekdusia, reveal this pattern of thought in its full form.