Leadership theory can provide a route for investigating teaching via the concept of instructor leadership. Instructor leadership is defined as a process whereby instructors exert intentional influence over students to guide, structure and facilitate classroom activities and relationships in a class. Instructor leadership in higher education research has focused primarily on constructive leadership. However, the classroom context is also conducive to destructive leadership. The objectives of this study are to (a) conceptualize destructive instructor leadership and (b) investigate the association between destructive instructor leadership and student reactions. Using 13 in-depth semistructured student interviews at management schools across various universities worldwide, the results of a thematic analysis indicate that destructive instructor leadership can be conceptualized as three dimensions, including callous communication, chaotic carelessness and irresponsibility. The interview data are then used to demonstrate that destructive instructor leadership is associated with students' affective, behavioural and cognitive reactions. Theoretically, this study (a) contributes the concept of destructive instructor leadership, (b) extends previous organizational behaviour research on destructive leadership by offering a multidimensional concept and (c) examines the reactions of two manifestations of destructive leadership. Limitations, suggestions for future research and practical implications are discussed.