Olaf Trygve Dalseg (15 September 1898 – 12 April 1987) was a Norwegian marketing agent.
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 (Institutt for Markedsføring), and was an honorary member of Norwegian Association of Advertising Agencies who owned the Institute.
[2] Already in 1947 he was honored with the Royal Norwegian Order of St. Olav for his fundraising for Nasjonalhjelpen.