Type one diabetes is a complex disease and may affect physical and mental health. These mental health effects include the impacts of stigma which may result from misconceptions. Physical health effects may include not following diabetes self-management behaviors, which increases the risk of short-term hypoglycemia complications and long-term hyperglycemia complications. This online study investigated how stigma affects type one diabetes self-management behaviors. This study sample was adults aged 18 years or older with type one diabetes. These participants were recruited from online social media platforms including Instagram, Reddit, Facebook, and LinkedIn accounts. Quantitative data was collected through an online survey and qualitative data was collected through an online interview. Results show that misunderstanding type one diabetes is a major factor that results in social stigma behaviors. As a result, the majority of adults with type one diabetes experience internal stigma and affected self-management behaviors to a certain extent, depending on the amount of support, education, and experience the individual has.