This chapter provides an overview of patient preference research, summarising the main methods and approaches, good practices for involving patients in preference research to increase the relevance and impact of patient preferences, and discusses how patient preferences can inform the health technology assessment (HTA) process. Patient preference research generates information from patients’ perspectives that can include the process of care delivery and non-health outcomes in addition to health outcomes. Patient preference research can be used to address a range of questions faced by decision-makers. These questions include identifying what aspects matter to patients (what is important), determining how much each aspect of care matters relative to one another (relative importance), and understanding the relative trade-offs between aspects of care. It can be also used to value patient care processes alongside clinical and health outcomes, value health states, and predict uptake and acceptability of health interventions and care. Drawing on the recommendations and guidance from international consortia and expert groups, patient preference research is illustrated using various case examples to highlight and discuss its application in HTA and decision making more broadly. Finally, the chapter identifies methodological challenges of patient preference research within an HTA context and areas for future research.