Through the guidance of social presence theory, this study sought to understand how instructors' affirming messages and social presence behaviors affect students' writing apprehension in online business communication courses. The data were consistent with two models, both of which indicate that instructor affirming messages indirectly affect students' writing apprehension in the business communication classroom. Both models also indicate that students' burnout mediates that indirect effect. The results show how important it is for instructors to take the time to leave affirming message feedback when teaching business communication online.