Yiannis Kouros (Greek: Γιάννης Κούρος, pronounced [ʝiˈa.nis ˈku.ros]; born 13 February 1956 in Tripoli, Kingdom of Greece) is a Greek ultramarathon runner based in Greece.

Kouros came to prominence when he won the Spartathlon in 1984 in a record time of 20 hours and 25 minutes.

It seems that twenty years later, in 2014, at the age of 58, Kouros retired from ultrarunning competition.

[9] Concerning the secret of his success, Kouros claims, "When other people get tired, they stop.

"[citation needed] Kouros has also written over 1,000 poems, several of which appear in his books, Symblegmata ("Clusters") and The Six-Day Run of the Century.