Many have noted the rise of the global in academic and popular discourse. We ask how this global frame of reference has been incorporated into secondary social science textbooks, a realm traditionally dominated by nationalist discourse. Utilizing a data set from more than 500 secondary school textbooks from around the world, spanning 1970–2008, we describe the incorporation of mentions of globalization and global citizenship into textbooks over time and then use a multilevel model to determine the textbook and country-level variables associated with mentions of each. We find that globalization and global citizenship are both predicted by the textbook content's reflection of the external world, including international events and mentions of human rights. However, no cross-national economic or political differences systematically predict incorporation of these topics. We argue that mentions of globalization and global citizenship in textbooks are two manifestations of a world culture that increasingly emphasizes interconnectedness in postnational society.