Rumex palustris, or marsh dock, is a plant species of the genus Rumex, found in Europe. The species was mentioned by Leonard Plukenet, based on a collection made by Isaac Rand. The authority of the accepted description, Rumex palustris, was James Edward Smith, in Fl. Brit. volume 1, on page 394 in 1800. The species epithet palustris is Latin for 'of the marsh' and indicates its common habitat.