; 27 August 1946 in Tirán, Moaña – 30 September 2009 in Madrid) was a Spanish botanist.

is used to indicate Santiago Castroviejo as an authority in the scientific description and classification of species.

[2] Santiago Castroviejo was a research professor at the Real Jardín Botánico (Spanish National Research Council), Director of the Real Jardín Botánico de Madrid between 1984 and 1994.

He was the scientific director of the Coiba Project at the Coiba Biological Station (Panama), principal investigator of the Flora iberica Project, principal investigator of the Anthos Project – Information System on Spanish Plants, member of the executive committee and the Steering Committee respectively of the projects: Euro+Med PlantBase and Species Plantarum Project-Flora of the World, President of the Spanish Royal Society of Natural History, Academician of the Real Academia de Ciencias Exactas, Físicas y Naturales and Médaille du Conseil de la Société Botanique de France, among other important scientific distinctions.

He supervised 19 doctoral theses[3] and authored more than 150 research papers published in national and international scientific journals.