This study investigates whether an increase in the demand for nonconventional work schedules helps explain the gender gap in career advancement. We look at employees of U.S. firms acquired between 2010 and 2014 and distinguish between same and different time-zone acquisitions. The idea is that time-zone differences between the headquarters and the newly acquired firm increase the demand for and value of working outside the standard working schedule. This, combined with social norms about women’s role as caregivers, puts female employees at a disadvantage relative to men. Based on Zephyr-LinkedIn matched data, our results show that women are about 9.5% less likely than men to be promoted in cross-time-zone acquisitions than in same-time-zone acquisitions. The gap rises to 10.6% for managerial occupations, and it is higher for time-zone differences of two and three hours. We discuss the implications of our results for the management, evaluation, and retention of human capital in organizations and, more generally, for gender equality in the workplace.