Professors create a positive learning environment for students through their interpersonal behaviour style in the classroom. High quality interpersonal interactions are associated with a number of positive student outcomes such as increased motivation, effort, learning, satisfaction, and higher ratings on formal student evaluations of teaching (SETs). This study tested a Self-Determination Theory model in a university setting by measuring the association between professors' reported psychological need satisfaction, teaching motivation, and self-reported supportive interpersonal behaviour styles, exploring how these variables related to SETs. Overall, we found support for the model; all relationships were significant and in the expected direction except that reported autonomy and competence supportive behaviours did not relate to SETs. From this, we can conclude that relatedness support is important to the student experience and that professors who engage in relatedness supportive interpersonal behaviours are also positively evaluated by their students.