Sandra Knapp is a plant taxonomist at the Natural History Museum in London focusing on the nightshade family (Solanaceae) whose members include both foods (potato, tomato, aubergine) and poisons (henbane, mandrake, tobacco). She works in lab, field and museum collections to unravel the mega-diversity of Solanum, one of the largest genera of flowering plants, by delimiting and describing species and clades to provide a solid baseline for her studies of biogeography, phylogeny and character evolution. Her work with crop wild relatives has influenced plant breeding for climate change. She has been instrumental in simplifying and modernising the international rules for naming algae, fungi and plants.

She received her PhD from Cornell University and holds honorary professorships at University College London and Stockholm University.

She is the recipient of the Peter Raven Outreach Award, the Sir John Burnett Medal, the Linnean Medal, the José Cuatrecasas Medal for Excellence in Tropical Botany, the Rolf and Gertrude Dahlgren Prize and the David Fairchild Medal for Plant Exploration. She is an elected member of Academica Europeana, the American Academy of Arts and Sciences and the Academica Nacional de Ciencias of Argentina.