The crucial role of teacher-student relationships has been reported in many studies. Yet, how teacher-student relationships develop from moment-to-moment interactions during lessons remains understudied. The present study combined insights from interpersonal theory and dynamic systems approaches to study indices of interpersonal content and structure in teacher-student interactions and their association with the teacher's interpersonal style. We found that moment-to-moment teacher behavior was indeed related to student perceptions of the teacher's interpersonal style. Indices of variability (structure) in interactions discriminated between teachers with less preferred and more preferred interpersonal styles, while, contrary to earlier research, the indicator of predictableness of interactions could not. Results are discussed considering the expectations, and suggestions made for future research and practice.