In analysing heterosexual couples’ work–family arrangements over time and space, the comparative social policy literature has settled on the framework of the ‘male-breadwinner’ versus the ‘dual-earner’ family. Yet, in assuming men in couple-families are (full-time) employed, this framework overlooks another work–family arrangement, which is the ‘female-breadwinner’ couple. Including female-breadwinner couples matters because of their growing prevalence and, as our analysis shows, greater economic vulnerability. We perform descriptive and regression analyses of Luxembourg Income Study microdata to compare household incomes for female-breadwinner couples and other couple-types across 20 industrialized countries. We then consider how labour earnings and benefit incomes vary for ‘pure’ breadwinner couples – comprising one wage-earner and one inactive/unemployed partner – according to the gender of the breadwinner. We find that pure female breadwinners have lower average individual earnings than male breadwinners, even after controlling for sociodemographic characteristics and occupational and working-time differences. Furthermore, welfare systems across most countries are not working hard enough to compensate for the female breadwinner earnings penalty, including in social-democratic countries. Once controls are included in our regression models, it never happens that pure female breadwinners have higher disposable household incomes than pure male breadwinners. Thus, our study adds to a growing body of evidence showing that female-breadwinner families sit at the intersection of multiple disadvantages. In turn, these couples offer comparative scholars of the welfare state an ‘acid test’ case study for how effectively families are protected from social risk. Our results additionally highlight how cross-national differences in the female breadwinner income disadvantage do not fit neatly with established welfare typologies, suggesting that other factors – in particular, labour market characteristics and the economic ...