This article examines the effect of composition of friendship networks during early adolescence on the likelihood of entering an interethnic union among the children of immigrants. We analyze the panel data from the Children of Immigrants Longitudinal Study that followed 14-year-olds into their early 20s. We extend previous research by simultaneously examining the effect of the social context and personal networks and by broadening the type of unions under consideration (i.e., dating and cohabiting unions in addition to marriage). In line with hypotheses regarding opportunities and preferences, we found, first, that having an ethnically diverse friendship network positively affects the likelihood of entering an interethnic union. Second, the effect of the friendship network is equally strong for dating, cohabitation, and marriage. Finally, the effect of the social context on interethnic partner choice is not mediated by the friendship network.