This study investigates how instructor teaching philosophy (traditional vs. constructivist) and type of learning space (traditional vs. active) influence instructor perceptions of student engagement. In a quasi-experimental study, we found that instructors perceived that students were more engaged in the active learning classroom (ALC) than in the traditional classroom. In addition, we found that instructors with a more constructivist philosophy perceived that students engaged more actively in learning. On closer analysis, however, the difference in perceived student engagement was only significant between more versus less constructivist philosophy when in the ALC. Finally, we found that the relationship between teaching philosophy and student engagement in the ALC was mediated by instructor behavior.