Background: Diabetes mellitus (DM) patients are prone to influenza infection. Seasonal vaccination is the most effective method to prevent influenza. Assessing the influenza coverage and the knowledge and attitude of patients toward it will help in raising the coverage and decreasing the complications. Objectives: To detect the level of influenza vaccination coverage among people with type 2 diabetes mellitus (T2DM) and assess the knowledge about influenza infection and attitude toward influenza vaccine among those patients. Methods: We conducted a cross-sectional study in the diabetes outpatient clinics at Zagazig University hospitals. The study included 327 diabetic patients. It took six months, from February to July 2023. A structured questionnaire was used to assess knowledge, attitudes, and practices regarding seasonal influenza vaccination and factors that may affect them. Results: The mean age of participants was 55.2 years; most of them were female (63.3%). The vaccination coverage was only 23.9%. Sufficient knowledge was reported (64.8%), and a positive attitude toward vaccination among those who had heard about it was reported (69.6%). The main cause of non-vaccination was that they didn’t hear about the vaccine (67.8%), while the main cause of vaccination was a doctor’s advice (62.8%). After logistic regression, sufficient knowledge and longer disease duration were found to be statistically significant predictors for vaccination (odds ratio 2.117, 1.081 respectively). Conclusions: The influenza vaccination rate among T2DM patients is below the optimal level. Overall, knowledge and attitude toward the influenza vaccine among diabetic patients should be raised.