Objective: The purpose of the study was to determine the knowledge and level of awareness about diabetes among adolescent students and to identify the factors that affect them. Material and Method: The present study, which had a descriptive design, was conducted between December 2019 and February 2020 among 684 students aged 10-15 years studying at three secondary schools in Kirklareli. The data were collected through face-to-face interviews using a questionnaire, which has been prepared on the basis of the literature. Findings: Of the adolescents, 90,9% were aware of diabetes, 48,2% had accurate knowledge. The most well-known propositions in the diabetes knowledge questionnaire were “Diabetic people should have healthy nutrition (83,2%)”, and “Children may have diabetes (81,7%)”. Significant differences (p<0,05) were found between the mean scores of the students for the level of knowledge about diabetes and student’s age, mother’s and father’s educational status, the status of having breakfast regularly, preferring fast-food at meals, diabetes awareness, presence of diabetes in the mother, father or sibling. No significant difference was detected between the students’ mean scores for diabetes knowledge in terms of gender, the status of exercising regularly, the presence of a disease that requires regular medication (p>0,05). Conclusion: Although almost all students were aware of diabetes, only half of them had accurate knowledge about diabetes. The studies that will increase the levels of knowledge and awareness about diabetes among students should be accelerated.