Policy debates in the U.S. are increasingly informed by use of internationally generated, comparative data. Many arguments revolve around whether or not such comparison makes “cultural sense” or whether specific educational activities that appear successful in one nation are “culturally appropriate” in another. These arguments clash with the work of anthropologists and sociologists who demonstrate that global cultural dynamics influence national patterns of schooling around the world. Using both the survey and case study data from the Third International Math-Science Study (TIMSS), we examine the working conditions and beliefs of teachers in Japan, Germany, and the U.S. in order to assess the relative merits of competing theoretical perspectives. We find some differences in how teachers’ work is organized, but similarities in teachers’ belief patterns. We find that core teaching practices and teacher beliefs show little national variation, but that other aspects of teachers’ work (e.g., non-instructional duties) do show variation. We show that models of national cultures of learning or “national teaching scripts” may overemphasize cultural differences and underestimate the impact of institutional isomorphism in schooling. We argue that rather than change values, educational policy will be best served by identifying specific features of teacher work and analyzing how to improve these working conditions.