The fact that women are still less likely than men to hold leadership positions is evident across Europe, with gender differences varying among countries. This paper examines how part-time employment contributes to the gender gap in leadership positions between women and men working in highly skilled occupations. In doing so, we pay particular attention to whether and possibly how the correlation between part-time work and a leadership position is mediated by gender, as employment levels and gender have often been confounded in empirical studies in the past. The analyses are based on European Union Labour Force Survey data and cover seven European countries. Our results confirm that part-time work is related to the gender gap in leadership positions in all countries studied, with a negative correlation between reduced working hours and holding a supervisory position, and with women being much more likely than men to work part-time. Our findings also suggest that part-time penalties, i.e. the negative association between reduced working hours and having supervisory responsibilities, are gender-specific, but in the sense that they are more pronounced for male workers. Our findings further imply that the extent of part-time penalties is not related to the prevailing part-time culture in a country.