We mark the 50th anniversary of the International Committee on Taxonomy of Viruses (ICTV) by presenting a brief history of the organization since its foundation, showing how it has adapted to advancements in our knowledge of virus diversity and the methods used to characterize it. We also outline recent developments, supported by a grant from the Wellcome Trust (UK), that are facilitating substantial changes in the operations of the ICTV and promoting dialogue with the virology community. These developments will generate improved online resources, including a freely available and regularly updated ICTV Virus Taxonomy Report. They also include a series of meetings between the ICTV and the broader community focused on some of the major challenges facing virus taxonomy, with the outcomes helping to inform the future policy and practice of the ICTV. AD -, 24 Woodland Way, Stevenage, Herts, SG2 8BT, UK. email@example.com. Department of Microbiology, University of Alabama at Birmingham (UAB), BBRB 276, 845 19th ST South, Birmingham, AL, 35294-2170, USA. Sunfield, Dawney Hill, Pirbright, Woking, Surrey, GU24 0JB, UK. Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungaria krt. 21, 1143, Budapest, Hungary. Invasive Insect Biocontrol and Behavior Laboratory, USDA, 10300 Baltimore Avenue, Bldg 007 Barc-West, Beltsville, MD, 20705, USA. The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK. Departments of Food Science, Molecular and Cellular Biology and Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada. Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux, 75015, Paris, France. NIH/NIAID/DCR Integrated Research Facility at Fort Detrick (IRF-Frederick), B-8200 Research Plaza, Fort Detrick, Frederick, MD, 21702, USA. Division of Molecular and Cellular Biosciences, National Science Foundation, Arlington, VA, 22230, USA. Department of Microbiology and Immunobiology, Harvard Medical School, 77 Ave Louis Pasteur, Boston, MA, 02115, USA. Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, 100 Old Hwy 12 Mail Stop 9775, Starkville, MS, 39762, USA. Summerland Research and Development Centre, Agriculture and Agri-Food Canada, 4200 Highway 97, Summerland, BC, V0H 1Z0, Canada. School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, University of Bristol, University Walk, Bristol, BS8 1TD, UK. Nuffield Department of Experimental Medicine, University of Oxford, Peter Medawar Building, South Parks Road, Oxford, OX1 3PS, UK. The Biodesign Center for Fundamental and Applied Microbiomics, School of Life Sciences, Center for Evolution and Medicine, Arizona State University, P.O. Box 874701, Tempe, AZ, 85287-4701, USA. Departamento de Fitopatologia/BIOAGRO, Universidade Federal de Vicosa, Vicosa, MG, 36570-900, Brazil. MRC, University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, 464 Bearsden Road, Glasgow, G61 1QH, UK. Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, UK. Department of Medical Microbiology, Leiden University Medical Center, E4-P, rm. E4-72, P. O. Box 9600, 2300 RC, Leiden, The Netherlands. Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119899, Moscow, Russia.