The meaning of marriage and cohabitation has changed, potentially altering how people with higher relationship quality progress family formation, by getting married and/or having a first birth. They employ a cross-national perspective to study how relationship quality is associated with the likelihood of marriage and first birth within cohabitation and how this differs by country context. They raise questions about whether cohabitors with higher relationship quality are as likely to have a first birth as married couples in contexts where cohabitation is widespread. Using the Generation and Gender Survey and UK Household Longitudinal Study, they study seven European countries (Austria, France, Hungary, Netherlands, Norway, Sweden, and UK). They employ competing risk hazard models to follow respondents as they 1) transition from cohabitation into marriage or childbearing outside marriage 2) transition from marriage or cohabitation into parenthood. Results indicate that cohabitors with higher relationship quality have higher marriage risks in Austria, France, Hungary, and the UK, but not in the Netherlands, Norway and Sweden. Instead, higher relationship quality is associated with higher first birth risks in cohabitation in Sweden and Norway. Furthermore, married couples have a higher risk of first birth irrespective of relationship quality in most countries. These findings suggest that in contexts where the meaning of marriage and cohabitation are more similar, couples with higher quality relationships progress their relationships by having a first birth rather than marriage, although sizeable variation remains.