In the present study, complex dynamic systems theory and interpersonal theory are combined to describe the teacher-student interactions of two teachers with different interpersonal styles. The aim was to show and explain the added value of looking at different steps in the analysis of behavioral time-series data (i.e., observations of teacher and student behaviors) that are described by Warner (1998): (1) the general level and overall coordination, (2) the presence of linear, quadratic and cubic trends in behavior, (3) the coherence and phase in cyclical trends that are superimposed on the linear, quadratic and cubic trends, and (4) the residual fluctuations, when studying the fit between teacher and student interpersonal behavior. Interactional fit is conceptualized, and described in each step of the time-series analysis, using the principle of complementarity (e.g., Kiesler, 1996). Results showed that the teacher-student interactions of the teacher with the most desirable interpersonal style largely followed the complementarity principle, whereas the interactions of the teacher with the less desirable interpersonal style did not. These results are discussed in light of the hypotheses and limitations of the study.