Gustav Nicolay Aarestrup (1 January 1916 – 15 November 2005) was a Norwegian jurist and businessperson. He was both chief executive officer and chair of Storebrand.
He was born in Steinkjer as a son of vicar Joachim Homboe Aarestrup (1866–1940) and his wife Anna Sophie Wiig (1872–1944). The family moved to Sagene two years later.
He finished his secondary education in 1933, took Oslo Commerce School in 1934 and took the cand.jur. degree in 1938. He worked as a junior solicitor in Mysen until 1940, then briefly as a police officer in Oslo before being deputy judge in Farsund from 1940 to 1941. In July 1941, one year after the German invasion and occupation of Norway, Aarestrup was arrested for an attempt to flee the country. He was first imprisoned in Kristiansand's Arkivet, and later sat in Møllergata 19 from 8 to 22 August and in Grini concentration camp until mid-October 1941.
In 1942 he left Farsund, being hired in the insurance company Storebrand. After a year as a secretary for the American finance attaché in Sweden in 1944 and for the Ministry of Foreign Affairs-in exile in London from 1944 to 1945, he returned to Norway where he became foreign superindendent in Storebrand. Also, in 1943 he had married Ingrid Christie Krohn, daughter of professor Ivar Trygve Krohn and Ellen Christie.
He rose in the hierarchy, via board secretary from 1948, assisting director from 1954 and vice president from 1957 to 1961. He was the chief executive officer from 1965 to 1976. He then chaired the board until his retirement in 1982. In both 1965 and 1976 he succeeded Per M. Hansson. During his time as chief executive of Storebrand, he was also the chief executive of Custos, Europeiske, Hypotekforsikringsselskapet, Kreditt-Atlas and Oslo Assuranceselskap. In 1970 he also took over for Hansson as chief executive of Norrøna. From 1971 to 1974 Aarestrup chaired the Association of Norwegian Insurance Companies.