Janko Gredelj (28 March 1916 – 23 December 1941) was a Yugoslav communist and one of the organizers of the antifascist struggle in Zagreb in 1941.
After invasion of Yugoslavia by Axis powers in 1941, he was one of the organizers of the shock groups at the railway in Zagreb.
He participated in a few diversions: attack at the Gestapo agents in Bukovačka street and theft of 60 rifles, 10,000 bullets and some hand grenades from Germans' wagons at the West railway station in Zagreb.
After that, he was appointed to work in illegal press cell of the Communist Party of Croatia in Klaićeva street.
Ustasha agents discovered illegal press room on 23 December 1941, and tried to arrest Gredelj.