Scholars who have studied the effects of early pubertal timing on girls' sexual debut contend that this association may result from the company they keep. Although this basic biosocial model of adolescent behavior has been applied to various outcomes with diverse samples of adolescent girls, less work has contextualized this microlevel developmental phenomenon within the larger macrolevel structures of race and ethnicity. Using a sample of White, African American, and Latina girls (N=1,299) drawn from the National Longitudinal Study of Adolescent Health, this study conducted within-group multivariate analyses and found important differences in the linkages that make up this biosocial model by race and ethnicity, with the linkages strongest for Whites, followed by Latina, and African American girls. These differences in association may reflect differences in the social construction of girlhood across race and ethnicity.