© 2012 Springer Science+Business Media, LLC.The research study investigated the possible associations among science and biology teachers' knowledge and belief variables concerning teaching evolution in science and biology classes. Specifically, this study examined how a set of variables including teachers' understanding of evolution and nature of science (NOS) is related to the set of variables including teachers' acceptance of evolution and perceptions of teaching evolution (i.e., perceptions of the necessity of addressing evolution in their classrooms, perceptions of the factors that impede addressing evolution in their classrooms, and personal science teaching efficacy beliefs regarding evolution). Data were collected from science and biology teachers through administration of Evolution Content Knowledge Test, Measure of Acceptance of the Theory of Evolution, Nature of Science as Argument Questionnaire and Teachers' Perceptions of Teaching Evolution Scale. Canonical correlation analysis findings suggested that teachers who had thorough understanding of evolution and NOS were likely to both accept the scientific validity of evolution and believe the necessity of addressing evolution in the classrooms. On the other hand, teachers with thorough understanding of evolution and NOS did not necessarily believe that they have a stronger sense of self-efficacy beliefs regarding teaching evolution and that there are fewer obstacles to addressing evolution in the classroom. The research is significant in that it provides empirical evidence clarifying the interactions between teachers' understanding and beliefs in teaching evolution. Implications for science teacher education are discussed.