Professor David John Mabberley AM, (born May 1948) is a British-born botanist, educator and writer.  Among his varied scientific interests is the taxonomy of tropical plants, especially trees of the families Labiatae, Meliaceae and Rutaceae. He is perhaps best known for his plant dictionary The plant-book. A portable dictionary of the vascular plants. The third edition was published in 2008 as Mabberley's Plant-book, for which he was awarded the Engler Medal in Silver in 2009. As of June 2017 Mabberley's Plant-book is in its fourth edition.
 Born in Tetbury, Gloucestershire, England, Mabberley won a scholarship to Rendcomb College, Cirencester, then an open scholarship to St Catherine's College, Oxford, where he graduated B.A. in 1970 and M.A. in 1974. Although he intended to work for a doctorate under the cytologist C. D. Darlington he was inspired to move to Sidney Sussex College, Cambridge, under the supervision of E. J. H. Corner, leading to a PhD in 1973 and D.Phil. (Oxon) in 1975. In 1973 Mabberley was elected the first Claridge Druce junior research fellow at St John's College, Oxford, before being appointed in 1976 to a tutorial fellowship at Wadham College, Oxford (linked to a university lecturership in the Department of Botany, later Plant Sciences, where he set up the "Mablab" with graduate students and post-doctoral research workers from around the world). He served as Dean of Wadham College for many years. Some of the social aspects of Mabberley's period as Dean of Wadham are dramatized in Stephen Henighan's novel The World of After.  Mabberley was senior proctor at Oxford 1988–1989, later becoming Curator of the Oxford University Herbaria.  He has also served in various capacities at numerous universities around the world, including University of Paris (France), University of Leiden (the Netherlands), University of Peradeniya (Sri Lanka), University of Kuwait, Western Sydney University and Macquarie University (both in New South Wales, Australia). From 1995 he held a chair at the University of Leiden, where he is now Emeritus Professor.
 Mabberley moved to Australia late in 1996 and ran his own consultancy business there, one contract being as CEO of Greening Australia (NSW). In 2004 he was appointed to the Orin and Althea Soest Chair in Horticultural Science at the University of Washington, Seattle, US, where he was also Professor of Economic Botany in the College of Forest Resources. During his tenure there, he oversaw the union of the Washington Park Arboretum, Center for Urban Horticulture, Union Bay Natural Area, Elisabeth C. Miller Library and Otis Douglas Hyde Herbarium as the University of Washington Botanic Gardens, of which he was the founding director.  In March 2008 he took up the newly created position of Keeper of the Herbarium, Library, Art and Archives at the Royal Botanic Gardens, Kew.
 Mabberley is known as a world traveller, having performed fieldwork in many countries over several decades:  Kenya (1969, 1970–71), Uganda (1970–71), Tanzania (1971–72), Madagascar (1971), Malaysia, Singapore & Indonesia (1974, 1981), Papua New Guinea (1974, 1989), Seychelles (1978), Panamá (1978–79), Portugal (1984–96), New Caledonia (1984), New Zealand (1990), Sri Lanka (1991), Hawai’i (1998), Cape York, Australia (Royal Geographical Society of Queensland expedition, 2002), Malaysia (2003, 2007), Vietnam (2005), China (2006, 2008), India (2019), Japan (2019).
 During research for his PhD dissertation, he travelled widely and collected plants throughout eastern Africa and Madagascar (1970–2), making particularly significant pioneering collections in the Ukaguru Mountains, Tanzania, where he collected at least 14 species of plants (and one new snail species) new to science and restricted to that range. These include a species of coffee, a giant lobelia (Lobelia sancta (Campanulaceae)), a (hairy) balsam (Impatiens ukagurensis (Balsaminaceae)), besides Keetia davidii (Rubiaceae) and Senecio mabberleyi (Compositae), both named after him. He is also commemorated in Aglaia mabberleyana (Meliaceae) from Borneo, Begonia mabberleyana (Begoniaceae) from Sulawesi and Cinnamomum mabberleyi (Lauraceae) from Vietnam and Laos, besides Homalomena davidiana (Araceae) and Harpullia mabberleyana (Sapindaceae), both from New Guinea and Grewia mabberleyana (Tiliaceae) from Madagascar.
 In August 2011 Mabberley became executive director of the New South Wales Royal Botanic Gardens and Domain Trust, Australia. In this capacity he was responsible for the management of Sydney's Royal Botanic Garden and Domain, The National Herbarium of New South Wales, The Australian Botanic Garden at Mount Annan near Camden and The Blue Mountains Botanic Garden, Mount Tomah. He left the post in September 2013 and shortly afterwards was elected to an Emeritus fellowship at Wadham College, Oxford. In honour of his seventieth birthday, colleagues and former students prepared a Festschrift, presented to him at Singapore Botanic Gardens, 27 September 2019.
 His archive, especially that relating to Mabberley’s plant-book is housed at the National Botanic Garden of Wales, of which he was a Trustee 2008-2011 and is an Honorary Fellow since November 2018.
 Among the awards he has received are the José Cuatrecasas Medal for Excellence in Tropical Botany and the Peter Raven Award (by the American Society of Plant Taxonomists "to a plant systematist who has made successful efforts to popularize botany to non-scientists"), both in 2004. In 2006 he was awarded the Linnean Medal of the Linnean Society of London and, in 2011, the Robert Allerton Award for Excellence in Tropical Botany of the National Tropical Botanical Garden, USA. He is a Corresponding Member, American Society of Plant Taxonomists (since 1999) and Fellow, Indian Botanical Society (since 2015).
 In 1993 he was elected President of the Society for the History of Natural History. In 2005 he was elected President of the IAPT.
 In 2016 he was appointed a Member of the Order of Australia for significant service to horticultural science, particularly to plant taxonomy and tropical botany, as an academic, researcher and author.
 In 2018 he was presented with the award of Doctor of Science (DSc honoris causa) by the Vice-Chancellor of Macquarie University in recognition of his outstanding contribution to horticultural science.