Abstract: This study sought out to investigate level three students’ misconceptions affecting performance in trigonometry in two selected schools of Kicukiro District. The target population was 386 level three students in selected TVET schools located in Kicukiro District for 2021-2022 academic year. Among these schools, one public and one private school were chosen purposively and a sample of 196 participants was taken using stratified sampling methods so that each trade in the selected schools was represented. This study followed a descriptive survey research design and the data from selected participants were collected using questionnaires and analysed using SPSS. The results indicated that 70% of the students have positive attitudes towards trigonometry and they were interested in this unit, but trigonometric concepts were not explained clearly and they were not familiar with notations. They also have misconceptions in making invalid references and conceptual misunderstanding on trigonometric ratios, trigonometric equations and solving word problems. The study recommends trainers to motivate their trainees in learning trigonometry, to explain trigonometric concepts clearly; provide more exercises, including word problems, and advise trainees to avoid carelessness while doing assignments.