The purpose of the 2020 Asthma and Respiratory Foundation NZ Adolescent and Adult Asthma Guidelines is to provide simple, practical and evidence-based recommendations for the diagnosis, assessment and management of asthma in adolescents and adults (aged 12 and over) in a quick reference format. The intended users are health professionals responsible for delivering asthma care in the community and hospital settings, and those responsible for the training of such health professionals. The main changes in the 2020 update are: 1) combining the recommendations for both adolescents and adults in a single document, 2) the recommendation to avoid SABA-only treatment in the long-term management of asthma, 3) the use of budesonide/formoterol reliever, with or without maintenance budesonide/formoterol, is preferred to SABA reliever, with or without maintenance ICS or ICS/LABA, across the spectrum of asthma severity, 4) introduction of the terminology 'anti-inflammatory reliever (AIR)' therapy to describe the use of budesonide/formoterol as a reliever medication, with or without maintenance budesonide/ formoterol therapy. This approach encompasses and extends the 'Single combination ICS/LABA inhaler Maintenance And Reliever Therapy' (SMART) approach recommended in the previous guideline, 5) the inclusion of two stepwise management algorithms, 6) a clinical allergy section, 7) the role of LAMA therapy in severe asthma, 8) the role of omalizumab in severe allergic asthma and mepolizumab in severe eosinophilic asthma, 9) an appendix detailing educational materials.