["Family Relations, EarlyView. ", "\nABSTRACT\n\nObjectives\nThis study examined heterogeneity in interethnic parents' ethnocultural affiliations and compared affiliation profiles on interparental relationship quality and coparenting as well as mixed‐ethnicity children's mental health.\n\n\nMethods\nParticipants were mothers (Mage = 24.69 years at child's birth), fathers (Mage = 27.51 years at child's birth), and their children (49.2% girls; Mage = 15.61 years at adolescence) from 660 multiethnic families of Black‐Hispanic, Hispanic‐White, or Black‐White backgrounds. Parents reported on ethnocultural affiliation at the birth of their child, on relationship functioning at child age 3, and both parents and adolescents reported on children's mental health at age 15.\n\n\nResults\nFour profiles of ethnocultural affiliation were identified amongst interethnic parents. Relationship quality was highest in the profile marked by fathers' higher and mothers' lower ethnocultural affiliation. Multiethnic children were rated as having the fewest internalizing and externalizing difficulties in the profile marked by moderately high fathers' and high mothers' ethnocultural affiliation.\n\n\nConclusions\nThe findings provide evidence of heterogeneity in interethnic parents' ethnocultural affiliations, and initial indications of differential parent and child outcomes depending on this heterogeneity.\n\n\nImplications\nThe results serve as a foundation for future research on understanding the diverse experiences of interethnic parents and multiethnic families.\n\n"]