Ruşen Eşref Ünaydın (1892–1959) was a prominent Turkish author, journalist, diplomat, and politician who played a significant role in the cultural and political formation of the Republic of Turkey. He is best known for introducing the interview (mülâkat) and reportage genres to Turkish literature.

His most famous work, Diyorlar ki ("They Say," 1918), is considered the first high-quality example of the interview genre in Turkish literature, featuring conversations with 18 major writers of the period.

He was one of the first journalists to interview Mustafa Kemal Atatürk after the Battle of Gallipoli. This interview, titled Anafartalar Kumandanı Mustafa Kemal ile Mülâkat, helped introduce the future leader of Turkey to the public.

Institutional Founder: He was a founding member and the first General Secretary of the Turkish Language Association (Türk Dil Kurumu). He was also among the founders of Galatasaray S.K..

He served as a Member of Parliament for Afyonkarahisar and held various diplomatic posts, representing the young Turkish Republic abroad.