Offices are social places. Employees and managers take breaks together and talk about family and hobbies. In this study, we show that employees' social interactions with their managers can be advantageous for their careers, and that this phenomenon contributes to the gender pay gap. We use administrative and survey data from a large financial institution and exploit quasi-random variation induced by the rotation of managers. We provide evidence that when employees have more face-to-face interactions with their managers, they are promoted at a higher rate. This mechanism could explain a third of the gender gap in promotions at this firm.