We examine the impact of culture on the work behaviour of second‐generation immigrant women in Canada. We contribute to the literature by analysing the role of intermarriage in intergenerational transmission of culture and its effect on labour market outcomes. Using female labour force participation and total fertility rates in the country of ancestry as cultural proxies, we find that culture affects the female labour supply. Cultural proxies are significant in explaining number of hours worked by second‐generation women with immigrant parents. The impact of culture is significantly larger for women with immigrant parents who share the same ethnic background than for those with intermarried parents. The weaker effect of culture for women raised in intermarried families stresses the importance of intermarriage in assimilation process. Our findings imply that government policies targeting women's labour supply may have differential effects on the labour market behaviour of immigrant women of different ancestries.