Occupational positions can explain an important part of the differences in pay between men and women. However, a considerable Gender Pay Gap exists even within the same occupational position. In this paper, we aim at understanding the reason for the gap within occupational positions and, therefore, investigate whether promotions lead to the same effect on earnings growth for men and women. Using unique data on the total population of all employees subject to social security, we are the first to estimate the gender gap in earnings growth after promotions in Germany. Our first results emphasize that women’s earnings growth is lower than men’s after being promoted within the same position. This effect cannot be explained by motherhood as this holds also true for childless women. However, the effect disappears when we add firm-fixed effects. This finding suggest that women select into firms where promotions lead to lower earnings growth.