James Donn (1758–1813) was an English botanist and gardener. He was trained by William Aiton, a protege of Sir Joseph Banks and was Curator of the Cambridge University Botanic Garden, Cambridge, from 1790 until his death. His most important work was Hortus Cantabrigiensis, first published in 1796 but with several later, much expanded, editions. It carried on past his death until 1845.