The current longitudinal study of 323 Latino adolescents (50.5% male; M age = 15.31 years) examined whether ethnic identity exploration, resolution, and affirmation demonstrated significant growth over a 4-year period and whether growth in ethnic identity predicted growth in self-esteem. Findings from multiple-group latent growth curve models revealed that exploration, resolution, and affirmation all increased significantly from middle to late adolescence for Latina girls. For Latino boys, only affirmation increased significantly. Furthermore, only growth in exploration predicted growth in boys' and girls' self-esteem. This research indicates that patterns of growth in ethnic identity vary by adolescent sex. Furthermore, findings underscore the need to examine the unique contributions of each ethnic identity component, rather than using a composite ethnic identity score.