Purpose of Review <p>To provide a working definition of underserved populations in headache medicine for use in clinical and research settings. </p> Recent Findings <p>Prior research has identified disparities in headache care access, disease prevalence and burden in US populations by geographic location, poverty or disability status and for members of racial, ethnic or sexual and gender minority groups, or vulnerable groups such as new migrants. Research studies typically exclude other populations (pediatric, geriatric and pregnant/breastfeeding), which may limit the quality of headache care they receive.</p> Summary <p>We propose that underserved populations in headache medicine is broadly defined as those facing barriers in access to headache care – specifically, individuals living in rural or geographically underserved areas, who are uninsured, underinsured or living in poverty, with disabilities, from historically marginalized racial/ethnic groups, who are LGBTQIA+, or vulnerable groups such as new migrants, asylum seekers and those with an undocumented status.</p>