The study of adolescent childbearing is a major public policy concern, and father involvement is a particular focus. Previous research with married couples has found that coparenting may be a better predictor of father involvement than relationship quality. The current study examined 94 primiparous African American and Latino parents to determine whether coparenting expectations during pregnancy better predict concurrent father involvement secondary to a mediation effect. Results were mixed; simple mediation was supported, but structural equation modeling (SEM) results suggested a better fitting model for mothers than for fathers. For mothers, relationship quality predicted coparenting. For fathers, relationship quality and coparenting predicted father involvement, but relationship quality did not predict coparenting. This examination suggests that both relationship quality and coparenting are important for father involvement in unmarried adolescents but to differing degrees for mothers and fathers. Pregnancy may be an important potential intervention point for increasing subsequent father involvement.