Teaching conditions have been an enduring concern for North American teachers for over a century. This paper explores this phenomenon by tracing how teaching conditions have been understood by decision makers and in educational research over time. It draws on historical research on the formation of mass public education systems to consider why the conditions teachers identify as critical to their work have been so persistently ignored by policy makers and researchers. Then we review the major ways that teaching conditions have been understood to matter in educational research, focusing first on psychological understandings about the relationship between working conditions and teacher motivation and then on the organizational factors teachers identify as critical to their sense of efficacy and job satisfaction. These two conceptualizations, however, are limited in their explanatory power because they are embedded in a bureaucratic framework where teachers are understood primarily as implementers of policy decisions made by their organizational superiors. Attempting to understand the full power of teaching conditions requires a more comprehensive understanding of teaching and learning processes closer to the ground. We provide descriptions of teachers' work emerging from a recent study in order to demonstrate the close and reciprocal relationships between teaching conditions and students' opportunities to learn. (Contains 4 figures and 1 note.)