Osman Sadi Eldem (1910–1995) was a Turkish diplomat and served as the ambassador of Turkey to Spain between 1969 and 1972 and then to Iran from 1972 to 1975.

[1] His mother, Azize Hanım, was the granddaughter of the Ottoman statesman and Grand vizier Ibrahim Edhem Pasha.

[1] Sadi graduated from Galatasaray High School and received a degree in law from Istanbul University.

[4] Eldem married a daughter of Ottoman princess Naciye Sultan, Rana Hanımsultan, on 25 July 1949.

On 2 September 1983 he married Zeynep Sedef Torunoglu, and they had a daughter, Simin Eldem (born on 2 January 1987).