The associations between teaching behaviors and students’ affect are examined in cross-sectional studies in younger samples, but the temporal direction of these associations in high school students is unknown. In this longitudinal study, adolescents (N = 188; 88.8% White; 69.7% female) completed instruments to measure teaching behaviors and adolescents’ negative (e.g., cheerful) and positive affect (e.g., ashamed) twice, four months apart. Adolescents’ negative affect predicted future negative teaching behavior and negative teaching behavior marginally predicted adolescents’ future negative affect. Positive affect predicted future socio-emotional teaching behavior and vice versa. The findings provide insight into which teaching behaviors impact students’ affect and the impact that students’ mental health has on teaching behavior, an area of study that has received limited attention.