This study was conducted to model how teacher misbehaviors associate with reductions in students' sustained attention. Participants (N = 423 college students) responded to measures of their perceptions of teacher antagonism, affect for their instructor, intrinsic motivation to learn, and sustained attention throughout the semester. Results of a path analysis indicated that teacher antagonism did not impact students' sustained attention directly or indirectly through their affect for the instructor or intrinsic motivation (individually, as simple indirect effects). Rather, results from a serial multiple mediator model demonstrated that the effect of teacher antagonism on students' sustained attention occurred through a reduction in affect for their instructor and, in turn, a reduction in intrinsic motivation to learn. Results are discussed with regard to the potential impact on student learning and best practices in the classroom.