Ann Rheum Dis 2021;80:31–35.A significant proportion of people with RA remain symptomatic despite treatment according to current management recommendations. Different terms have traditionally been used to describe this subpopulation, including severe, refractory, resistant to multiple drugs or treatments, established and difficult-to-treat. A recent survey indicated that – in addition to new drugs – new management approaches are needed for optimal treatment in these patients.A EULAR Task Force agreed the uniform terminology of ’difficult-to-treat RA’ as this best captures the possible clinical scenarios. A survey among rheumatologists identified key characteristics. The survey results, proposed terminology, and draft definition were discussed at a Task Force meeting, where detailed wording was discussed and amended until consensus was reached.The new definition includes three key elements: treatment failure, characterisation of active or symptomatic disease, and clinical perception. This definition for difficult-to-treat RA can be used in clinical practice, clinical trials, and can form a basis for future research. EULAR is developing management recommendations for difficult-to-treat RA, aiming to cover all inflammatory and non-inflammatory factors.