The authors examined the knowledge of middle level mathematics teachers instructing in inclusive classrooms to the hearing impairments students (HISs) or learning disabilities students (LDSs). The focus was on teachers' understanding of students' misconceptions related to the concept of angles. The study aimed to investigate the teachers' role in identifying the underlying perceptions of misconceptions among HISs and LDSs as well as their ability to offer effective solutions. The mathematics teachers responsible for HISs and LDSs were the subjects of this cross-case study, with the unit of analysis being teachers' knowledge of misconceptions concerning the concept of angles. Face-to-face interviews were employed to collect data, and subsequent analysis utilized a cross-case approach. The study findings revealed that both groups of teachers encountered numerous misconceptions for the first time. While teachers of HIS (HIST) identified the source of misconceptions as either teachers or students, teachers of LDS (LDST) more frequently attributed misconceptions to teachers and employed various representations to address and dispel these misconceptions. The authors recommended that teachers develop deep understanding of their students and identify potential misconceptions and that they explore diverse methods for taking precautions to prevent misconceptions.