This conceptual essay explores the role a teaching philosophy plays in the experiences of K-12 classroom teachers who are firmly established in a school context. We draw on our experiences as in-service teacher educators and K-12 teachers to examine the extent to which teachers make decisions that are grounded in a well-thought out and clearly articulated belief system about teaching and learning. We argue that there are often tensions and disconnections between teachers' fundamental beliefs about teaching and learning and the realities of current mandates and imposed expectations.