We investigate the link between premarital cohabitation and trajectories of subsequent marital quality using random effects growth curve models and repeated measures of marital quality from married women in the NLSY-79 (N = 3,598). We find that premarital cohabitors experience lower quality marital relationships on average, but this is driven by cohabitors with nonmarital births. Premarital cohabitors without nonmarital births report the same marital quality as women who did not cohabit before marriage. Nonmarital childbearing is more strongly associated with lower subsequent marital quality for White women than for Black or Hispanic women. Marital quality declines at similar rates for all couples regardless of cohabitation or nonmarital childbearing status. These findings are robust to numerous alternative model specifications.