Event-based Social Networks (EBSN) have become extremely popular in recent years. In this new type of social media, users organize, manage and share social events. In conjunction with EBSNs, several entities such as event planning and marketing companies, organizations, as well as venues, organize and manage numerous social events (e.g., festivals, conferences, parties). A major challenge for event organizers is attracting the maximum number of participants, since it has great impact on the success of the event, and, consequently, the expected gains (e.g., revenue, artist/brand publicity). In this work, we introduce the Social Event Scheduling (SES) problem, which schedules a set of social events considering user preferences and behavior, events’ spatiotemporal conflicts, and competing events, in order to maximize the overall number of participants. In short, given a set of events, a set of time periods and a set of users, our objective is to determine how to assign events on the time periods, so that the maximum participant enrollment is achieved.