Understanding the factors that promote civic engagement among emerging adult college students is crucial, especially considering its association with positive youth development. The current study examined ethnic-racial identity (ERI) exploration, resolution, and affirmation as mediators of the relation between cultural socialization and civic engagement. Additionally, the extent to which students were raised in predominantly minoritized neighborhoods (i.e., predominantly minoritized neighborhood racial composition; PMNRC) was included as a moderator of the associations between cultural socialization and ERI components. Last, we tested whether findings varied based on students’ ethnic-racial backgrounds (i.e., differences in the model for Asian, African American, Latinx, and Multiracial students of color; N = 1036). Results indicated that there was a significant mediation path, such that cultural socialization predicted greater ERI exploration and, in turn, greater civic engagement. Cultural socialization was also positively associated with greater ERI resolution and affirmation. The racial composition of the neighborhoods that individuals were raised in was not significantly associated with any ERI component; however, PMNRC moderated the relation between cultural socialization and ERI affirmation. Specifically, cultural socialization predicted more ERI affirmation at higher levels of PMNRC, but this relation was not significant at low levels of PMNRC. There were no significant ethnic-racial differences in relations we tested in the model. These findings highlight the importance of cultural processes in civic engagement among diverse emerging adults.