Debates over curricula can be understood as struggles over the power to define symbolic representations of the world. Although this tension is particularly visible in discourse around textbook adoption, this is not the only site of contestation; other aspects of the classroom environment, such as the posters on the walls, also contain implicit messaging about who belongs in school and who is an outsider. In this study, we examine K-12 classroom posters from nine popular websites and evaluate whether they were inclusionary of students' race, gender, sexuality, and (dis)ability and examined several factors that predicted inclusivity. Overall, we found that few posters had inclusive representations of individuals from historically marginalized groups and that academic posters were less likely to be inclusive than non-academic posters. This analysis provides insight into the messages students receive regarding who does and does not belong in the classroom and highlights the need for educators to purposively select the posters displayed in the classroom.