Background: Type 1 diabetes mellitus (T1DM) is one of the most frequent childhood chronic disorders. Teachers' awareness regarding diabetes and its complications could save students' lives. Aim of the study: To assess primary school teachers' knowledge and attitude regarding diabetic students. Research design: A cross-sectional design was used. Sample: A multistage sampling procedure was applied. A total number of 400 teachers was recruited for the study. Setting: This study was conducted in primary schools at Assuit City. Tools: An interviewer-administered questionnaire was used. It inquired about personal characteristics, knowledge about T1DM, and teachers' attitude toward T1DM. Results: Only 15% of the studied participants had a good level of knowledge about T1DM, while 64.8% had a positive attitude regarding T1DM. The adjusted significant predictors for increased knowledge about T1DM were being a diabetic patient, having diabetic students in their classes, receiving a previous training on T1DM, and having high scores of positive attitude of T1DM. Similarly, increasing knowledge level about T1DM significantly predicts a high positive attitude of T1DM. Conclusion: A low level of knowledge about T1DM was detected among primary school teachers despite a large proportion having a positive attitude toward T1DM. Recommendations: To improve teachers' knowledge about T1DM, it's recommended to integrate them into health education programs on T1DM before employment and in a regular manner.