Sep Ruf (full name Franz Joseph Ruf; 9 March 1908, in Munich – 29 July 1982, in Munich) was a German architect and designer, belonging to the Bauhaus group. He was one of the representatives of modern architecture in Germany after World War II. His elegant buildings received high credits in Germany and Europe and his German pavilion of the Expo 58 in Brussels, built together with Egon Eiermann, achieved worldwide recognition. He attended the Interbau 1957 in Berlin-Hansaviertel and was one of the three architects who had the top secret order to create the governmental buildings in the new capital city of the Federal Republic of Germany, Bonn. His best known building was the residence for the Federal Chancellor of the Federal Republic of Germany, built for Ludwig Erhard, the so-called Chancellor's Bungalow.
His father was Josef Ruf and his mother was Wilhelmine Mina Ruf (née Scharrer). The family of his father came from Dinkelsbühl and his mother's family lived in Weißenburg in Bayern, both in middle Franconia. He had a brother Franz Ruf born 1909. His first years at school he spent in a primary school in Munich. He was a Roman Catholic and went to the boy scouts, where he met friends, he had for his life time: Golo Mann, the son of the famous German writer and Nobel laureate in literature Thomas Mann and the later physicist and Nobel Prize laureate Werner Heisenberg. Until his years of study he went to the Luitpold-Oberrealschule and he loved skiing and climbing in the mountains. During this time he met his later fiancée, Aloisia Ruf, née Mayer, born in Munich, 2 April 1910, a daughter of a factory owner. They married 1938, built a home in Gmund am Tegernsee and had two children. His bureau was in Munich. Ruf loved to travel and he visited Austria, Italy, Greece, France, Belgium, Switzerland, the United States and Norway. 1969 he bought a winery in Italy and renovated the house. He became friend with many artists like Marino Marini and Bruno Pulga and had guests in Italy such as Henry Moore. He also kept in touch with Walter Gropius, Ludwig Mies van der Rohe, Richard Neutra and Romano Guardini. He is called to be the German architect, who realized the ideas of the Bauhaus most consequent. In 1982 he died in Munich and was buried at the mountain cemetery of Gmund am Tegernsee.