Epilepsy is one of the most common neurological disorders worldwide, and the majority of people with epilepsy who live in developed countries manage their condition with antiseizure medication. Surprisingly, therefore, the literature on epilepsy does not document a comprehensive investigation of patient adherence to medication treatment. This paper reviews existing literature on direct and indirect measures of adherence. Based on this review, areas in need for further research have been identified, including improvement of self-report instruments, consideration of cultural factors, attention to patient literacy or numeracy levels, and inclusion of patient-guided measures. While no single method of determining adherence has proved effective, combining direct and indirect measures in a patient-guided, culturally competent atmosphere may increase adherence to treatment, improving health outcomes for this population.