Siegfried Blechert (born 1 March 1946 in Aalborg, Denmark) is a German chemist.^[1]

Blechert studied chemistry at the University of Hannover, Germany and completed his PhD under the supervision of Ekkehard Winterfeldt in 1974. After a research stay with Pierre Potier in Gif-sur-Yvette, France, in 1981, he finished his habilitation at the University of Hannover in 1982 and there became lecturer in organic chemistry. In 1986 he took up a professorship at the University of Bonn. In 1990 he accepted the Chair of the Organic Chemistry Department at the Technical University of Berlin.^[2]

His research interests include the development of new catalysts for olefin metathesis, novel synthetic methods, and the stereoselective synthesis of natural products.^[1]