This paper reviews studies of teacher cognition in relation to the teaching of grammar in first, second, and foreign language classrooms. Teacher cognition encompasses a range of psychological constructs and these are reflected in the research reviewed here. Thus, in turn, I discuss studies of teachers' declarative knowledge about grammar, of their beliefs about teaching grammar, and of their knowledge as expressed through their grammar teaching practices. In addition to highlighting these different perspectives on the study of teacher cognition in grammar teaching, this review highlights key findings from the research and suggests directions for continuing inquiry in this field. (Contains 1 note.)