Understanding the social behaviors teachers believe is critical for school success and can contribute to the development of effective behavioral supports and assist teachers in better preparing students for successful school transitions across the K-12 grade span. We explored 1303 elementary, middle, and high school teachers' expectations of student behavior to examine the extent to which school characteristics (e.g., poverty, mobility, enrollment, school level) predicted teacher expectations. Our results corroborated findings of earlier studies indicating that teachers consistently placed greater emphasis on cooperation and self-control skills relative to assertion skills. Contrary to our expectations, we found that the level of school risk did not predict the importance teachers place on cooperation, assertion, and self-control skills. Some prominent differences, however, were found across elementary, middle, and high school levels, highlighting the importance of intentional communication and deliberate planning to help at-risk students transition across grade levels. We discuss limitations and future directions. (Contains 3 tables.)