Non-adherence to epilepsy medications can interfere with treatment and may adversely affect clinical outcomes, although few studies have examined this relationship. This study assessed barriers and drivers to adherence, its impact on quality of life, and the importance of the patient-physician relationship to adherence. Two cross-sectional online surveys were conducted among 408 adult patients with epilepsy and 175 neurologists who treat epilepsy patients. Twenty-nine percent of patients self-reported being non-adherent to antiepileptic medications in the prior month. Non-adherence was found to be associated with reduced seizure control, lowered quality of life, decreased productivity, seizure-related job loss, and seizure-related motor vehicle accidents. Patient-oriented epilepsy treatment programs and clear communication strategies to promote self-management and patients' understanding of epilepsy are essential to maximizing treatment and quality of life outcomes while also minimizing economic costs.