The negative impact of the visual limitations and disfigurement associated with Graves' ophthalmopathy (GO) for a patient's daily life has always been acknowledged in clinical practice. However, only recently have the effects of GO on health-related quality of life (HRQL) been quantified using validated questionnaires. In this article, a state of the art is presented on the aims, methodology and application of HRQL assessment in GO research. HRQL assessment is important in cross-sectional studies aimed at describing the severity of GO on multiple outcome levels, including the impact of GO on patients' daily functioning and perception of health in general, and in longitudinal studies aimed at the evaluation of treatment efficacy or comparison of the effects of different treatments on HRQL. Only a few studies have measured the effects of GO on HRQL directly. Patients with GO have a relatively low HRQL, not only in the period that they are diagnosed and treated for the disease, but their low HRQL persists even many years after the final treatment. Because the current therapies for GO are primarily directed at improving (visual) functioning and appearance, these treatments should be evaluated for their effectiveness on HRQL outcomes. At the moment, the recently developed GO-QOL questionnaire is the only validated disease-specific instrument available to measure HRQL in patients with GO. The GO-QOL is recommended as an instrument to measure GO treatment effects on HRQL.