This study investigated the role of ethnic identity in psychological adjustment. A sample of 209 college students in a multiethnic region completed questionnaires on ethnic identity, self-esteem, and ego identity. The results indicated that ethnic identity was positively related to self-esteem, especially with the affirmation and belonging component among Japanese and Filipino American students, and with the ethnic identity achievement component among multiethnic students. The overall relationship between ethnic and ego identities was positive, particularly in ethnic identity achievement scores. The combination of strong ethnic identity and a positive attitude toward other groups was related to advanced ego identity. Ethnic identity was different among ethnic groups, revealing that the development of ethnic identity is interactive in social contexts. Suggestions for future research and implications for multiculturalism are discussed.