This study examines the effect of teacher reasoning level (i.e., concrete versus formal) and teaching style preference (i.e., inquiry vs. expository) on improvement in student reasoning ability. A random sample of fourth and seventh grade teachers and their students were selected to participate over one school year. Students completed a reasoning test in the early fall and late spring. Teachers completed two instruments in the Spring, a reasoning test and a teaching style preference questionnaire. Students of concrete operational teachers showed greater gains in reasoning ability than students of formal operational teachers while students of inquiry teachers showed slightly greater gains than students of expository teachers. Possible explanations are discussed as are suggestions for future research.