This research examines whether being engaged and having a joint banking account influence relationship quality among cohabitors. Drawing on interviews with 936 young cohabitors from Wave III of the National Longitudinal Study of Adolescent Health, we estimated ordinary least squares regression of relationship quality on joint banking and engagement. The main effects of joint banking and engagement on relationship quality were both significant and positive, but their interaction was negative. These results indicated that nonengaged cohabitors with joint banking have levels of relationship quality similar to engaged cohabitors, but are advantaged relative to those who are neither engaged nor share a joint bank account. The results suggest the need for increased attention to joint-banking arrangements in cohabitation.