Modern digital technologies enable the efficient collection and processing of student perceptions of teaching quality. However, students' ratings could be confounded by student, teacher, and classroom characteristics. We investigated students' ratings of 26 teachers who used the digital tool Impact! in their mathematics lessons with 14- and 15-year-old students (n = 717). A Bayesian item response theory (IRT)-model approach was used to model potential associations. High-performing students on average rated their teacher higher than low- and middle-performing students. More likeable and more experienced teachers received higher ratings from their students, and the higher the class's average math grade, the higher the students rated their teachers. Other variables investigated in this study (e.g., student and teacher gender, class size) were not associated with student perceptions of teaching quality. Both related and unrelated factors are discussed. Some implications of the findings for practice, limitations of the study, and suggestions for further research are presented.