This study used the 1979 cohort of the National Longitudinal Survey of Youth (N = 3,481) to test whether the association between marital quality and divorce is moderated by premarital cohabitation or nonmarital childbearing status. Prior research identified lower marital quality as a key explanation for why couples who cohabit or have children before marrying are more likely to divorce than other couples. Using event history and fixed-effects models, we found that the effect of marital quality on divorce is similar for cohabitors and noncohabitors, with cohabitors more likely to end both high- and low-quality marriages. In contrast, the relationship between marital quality and divorce is weaker for women with nonmarital births; they are less likely than others to dissolve low-quality marriages. We discuss how commitment norms and self-efficacy might explain these differences in the association between marital quality and divorce. (Contains 3 tables and 1 figure.)