Olaf Christian Ditlev-Simonsen Jr. (2 January 1897 – 19 February 1978) was a Norwegian sailor, footballer, sports administrator and businessperson.

[1] Olaf Ditlev-Simonsen practised different sports in the club IF Ready, and, partly together with his four brothers, he won several Norwegian championships in bandy.

At the 1936 Summer Olympics he won the silver medal as crew member of the Norwegian boat Silja in the 8 metre event.

He was a board member of the Norwegian Shipowners' Association for some time, and during the Second World War he worked in Sweden, from 1943 as regional head of Nortraship.

Following his arrest he was transferred to Grini concentration camp on 13 January 1942 and given prisoner number 1274, being released on 21 September 1942.