Olaf Trygve Dalseg (15 September 1898 - 12 April 1987) was a Norwegian marketing agent.
He was born in Ringebu. He worked for the magazine Hjemmet and newspaper Morgenbladet and was also involved in film (directing the now-lost 1923 film Strandhugg paa Kavringen) before starting a career in marketing and advertising. His own marketing agency was named Dalseg Promotion. He was also affiliated with Institute of Marketing (Norwegian: Institutt for Markedsføring), and was an honorary member of Norwegian Association of Advertising Agencies who owned the Institute.[1] He received an honorary medal from the Nordic association in 1956.[2] Already in 1947 he was honored with the Royal Norwegian Order of St. Olav for his fundraising for Nasjonalhjelpen.[3] He died in 1987.[1]