Carl Friedrich Philipp von Martius (April 17, 1794–December 13, 1868) was a German botanist and explorer.

Martius was born at Erlangen, where he graduated M.D. in 1814, publishing as his thesis a critical catalogue of plants in the botanic garden of the university. He afterwards devoted himself to botanical study, and in 1817 he and Johann Baptist von Spix were sent to Brazil by the king of Bavaria. They travelled from Rio de Janeiro through several of the southern and eastern provinces of Brazil, and ascended the Amazon River to Tabatinga , as well as some of its larger affluents.

On his return to Europe in 1820 he was appointed conservator of the botanic garden at Munich, and in 1826 professor of botany in the university there, and held both offices till 1864. He devoted his chief attention to the flora of Brazil, and in addition to numerous short papers he published the Nova Genera et Species Plantarum Brasiliensium (1823-1832, 3 vols.) and Icones selectae Plantarum Cryptogamicarum Brashiensium (1827), both works being finely illustrated. An account of his travels in Brazil appeared in 3 vols. 4to, 1823-1831, with an atlas of plates, but probably the work by which he is best known is his Historia Palmarum (1823-1850) in 3 large folio volumes, of which one describes the palms discovered by himself in Brazil. In 1840 he began the Flora Brasiliensis, with the assistance of the most distinguished European botanists, who undertook monographs of the various orders. Its publication was continued after his death under the editorship of A. W. Eichler (1839-1887) until 1887, and subsequently of Ignaz von Urban . He also edited several works on the zoological collections made in Brazil by Spix, after the death of the latter in 1826.

On the outbreak of potato disease in Europe he investigated it and published his observations in 1842. He also published works and short papers on the aborigines of Brazil, on their civil and social condition, on their past and probable future, on their diseases and medicines, and on the languages of the various tribes, especially the Tupi. He died at Munich.

The standard botanical author abbreviation Mart. is applied to species he described.