Relatively little is known about what impacts perinatal outcomes in expectant mothers and fathers. In the current study, we examined the association between expected parenting efficacy and feelings of pregnancy responsibility on mental health and relationship satisfaction in 104 primiparous couples during their third trimester. Parenting efficacy was related to better perinatal mental health and relationship satisfaction for both mothers and fathers, while communal pregnancy responsibility was more important for mothers. At the couple level, being concordant on feelings of pregnancy responsibility was related to better mental health and relationship satisfaction for expectant mothers only. These results suggest the importance of examining predictors of perinatal outcomes, as well as the dynamic interplay between mothers’ and fathers’ feelings of pregnancy responsibility.