This thesis is a collection of three empirical studies on the impact of social origin on labourmarket outcomes across migration status and ethnic-origin categories. The existence of immigrant and ethnic penalties in the labour market is a recurrent finding. Migration research has, however, drawn little upon social stratification literature, despite sharing common concerns, to explain them. In this thesis, I seek to contribute to bridging the gap between the two disciplines. I pose two overall hypotheses: (i) compositional differences in social background across ethnic-minority groups and natives are likely to explain an important part of labour market penalties; and (ii) the strength of the effect of social origin on destination and its mechanisms of transmission might differ across groups. These hypotheses are tested by first using log-multiplicative layer effect models followed by different specifications of multivariate analyses based on data from Understanding Society. The findings show that: (i) class overrides ethnicity in explaining intergenerational mobility, although the strength of the OD association differs by ethnic origin and gender; (ii) labour-force participation is a gendered process with significant differences across migration status and ethnic origin, which are partly explained by the work status of the mother-in-law transmitted through partner/spouse’s characteristics; (iii) employment penalties are explained to a large extent by parental work status, education, and age, with variation in the strength of the effect of the last two factors across ethnic origin; and (iv) some groups experience more difficulties than natives with similar class backgrounds in employment as well as access to (and stable placement in) the salariat, although education exerts a compensatory effect. I conclude by arguing that future research should investigate further within-group explanations by deepening in the role of different mechanisms of intergenerational transmission of social (dis)advantage at different levels of the labour market.