Yrjö Aulis Uramo Blomstedt (28 February 1906 – 21 December 1979) was a Finnish architect and professor of architecture at the Helsinki University of Technology. He was a renowned modernist architect and architectural theoretician in the decades following the Second World War. Blomstedt was born into an architect family: his father Yrjö Blomstedt was an architect known for his National Romantic Jugend architecture, while his older brother Pauli E. Blomstedt was, until his premature death at the age of 35, a pioneering early modernist architect. His other brother, Jussi Jalas (formerly Armas Jussi Veikko Blomstedt), was a composer. Blomstedt was married to Heidi Blomstedt, the daughter of the composer Jean Sibelius. They had two children, the artist Juhana Blomstedt and the architect Severi Blomstedt.