Carl August Walther Sommerlath (22 January 1901 – 21 October 1990) was a German businessman and the father of Queen Silvia of Sweden. He was president of the Brazilian subsidiary of the Swedish steel-parts manufacturer Uddeholm Tooling after World War II.
He was born and raised in Heidelberg, Grand Duchy of Baden, German Empire (now Baden-Württemberg, Germany). His parents were Louis Carl Moritz Sommerlath (1860–1930) who was born in Chicago, Illinois in the United States who was from an armigerous family of the German Bourgeoisie, and his wife Erna Sophie Christine Waldau (1864–1944). In the mid 1920s, Walther Sommerlath moved to São Paulo, Brazil where he worked for the steel company Acus Roechling Boulerus do Brasil, a subsidiary in the German steel group Roechling.
On 10 December 1925 he married the Brazilian Alice Soares de Toledo (1906–1997), in Santa Cecília, São Paulo. She was the daughter of Arthur Floriano de Toledo and his wife Elisa de Novaes Soares. The couple had four children:
In 1938, Walther Sommerlath left Brazil and returned to Heidelberg. In 1939 he moved to the German capital Berlin.