Background: Clinicians are increasingly recognising severe asthma patients in whom biologicals and other add-on therapies lead to dramatic improvement. Because there is no agreed upon super-responder (SR) definition at present, we surveyed severe asthma experts using a modified Delphi process in order to define an international consensus-based definition of a severe asthma ‘super-responder’. Methods: The Delphi panel comprised 81 participants (94% specialist pulmonologists or allergists) from 24 countries and consisted of 3 iterative online voting rounds. Consensus on individual items, whether acceptance or rejection, required at least 70% agreement by panel members. Results: Consensus was achieved that the SR definition should be based on improvement across 3 or more domains assessed over 12 months. Major SR criteria included exacerbation elimination, a large improvement in asthma control (≥ 2x the minimal clinically important difference) and cessation of maintenance of oral steroids (or weaning to adrenal insufficiency). Minor SR criteria comprised a 75% exacerbation reduction, having well controlled asthma and a 500mL or greater improvement in FEV1. The SR definition needs to incorporate quality of life measures, though current tools can be difficult to implement in a clinical setting and further research is needed. Conclusions: This international consensus-based definition of severe asthma super responders is an important prerequisite for better understanding super-responder prevalence, predictive factors and the mechanisms involved. Further research is needed to understand the patient perspective and measure quality of life more precisely in super-responders.