By using data of seven countries drawn from the Gender and Generation Survey, we study the relationship between mothers’ employment and informal childcare provided by grandparents. Whereas intergenerational support encompasses several dimensions, childcare provided by grandparents is of particular interest. In general, we find that mothers’ employment is positively associated with grandparents providing childcare. However, grandparents differ in their preferences for performing childcare. The extent to which grandparent provide childcare depends on their age, health, activity status as well as the residential proximity to their children. But their provision of childcare also depends on their preferences and the interactions taking place between generations, all of which are unobserved in survey data. Those with a strong positive preference obviously provide more childcare, but they also have more traditional attitudes, which are reflected in a negative impact on mothers’ employment. Preferences for performing childcare are generally unobserved, and making the appropriate corrections in the empirical analysis shows that the effect of grand-parenting on mothers’ employment is understated when using standard regression techniques.