BACKGROUND: Diabetes treatment requires the use of medical sharps for glycemic control. Improper sharps collection and disposal poses substantial threats to people with diabetes (PWD), health care professionals, the environment, and public health. OBJECTIVES: To identify the prevalence and predictors of improper sharps collection practices among PWD in Saudi Arabia. METHODS: We surveyed 288 PWD at King Saud University Diabetes Center in Riyadh, Saudi Arabia, from September to October 2021. We asked questions about demographics, diabetes history, sharps collection practices, and prior education on proper sharps collection practices. We defined "proper sharps collection" as: using a designated sharps disposal container or homemade sealed container to collect sharps. RESULTS: Of the PWD surveyed, 60% were women, 54% were ≥35 years old, and 53% had type 1 diabetes. Most respondents (80% and 72%) reported improper collection of needles and lancets, respectively. Approximately, 56% of needle users and 61% of lancet users reported that they had never received instructions on safe sharps disposal. Receiving education on safe sharps disposal practices was associated with a 66% reduction in the risk of improper sharps collection practices (odds ratio (OR) [95% confidence interval (CI)]: 0.34 [0.16-0.68]) after adjusting for age, gender, type and duration of diabetes, income, education, and nationality of the study participants. Among those who improperly dispose their needles, 67% thought their sharps collection practices were appropriate. CONCLUSIONS: Our findings highlight the high prevalence of unsafe sharps collection practices among PWD in Saudi Arabia, and how prior education on safe sharps collection practices can help address this environmental and public health threat. Policies to reduce diabetes-related waste, unify the approach to proper sharps collection and disposal, and promote safe disposal education are needed to achieve a sustainable and safe waste management system.