Many studies have shown the importance of cultural capital for children’s educational success but little is known about the mechanisms of the intergenerational transfer of (receiving country-specific) cultural knowledge. This article analyses social and ethnic disparities in this transmission process with a focus on the mediating role of familial activities. With data from the German project ‘Preschool Education and Educational Careers among Migrant Children’, it is shown that 3–4-year-old children of well-educated, upper-class, and native German parents score significantly higher on a standardized test of cultural knowledge than children of low-educated, lower-class, and Turkish parents. Controlling for activities inside the families (like storytelling) and outside the families (like attending playgroups) reduces the effects of family background strongly and only the effect of the ethnic origin remains significant. Further analyses with the Turkish sample demonstrate that the positive effect of a higher frequency of familial activities on the children’s receiving country-specific cultural knowledge only holds under the condition that the parents mostly use German as communication language with their child. This interaction effect indicates that in immigrant families not only the frequency of familial activities is important but also their cultural content.