This study investigates the toxic leadership behaviours of school principals. It used a qualitative research model. Data were acquired based on interviews with 55 teachers from six school districts spanning diverse educational levels in Kuwait. The coding and data analysis process revealed that 45% (n = 25) of the participants considered their principals to be toxic leaders. In addition, the results confirmed that toxic leadership practices fall into four main groups: human relations skills, authoritarian leadership, management skills, and professional ethics. From these four groups, nine themes emerged as the most prominent toxic leadership practices.